Not one hundred meters from this hollow, is a little limestone cave,

closed by a wooden door, which excludes any cold air in winter.

The cave is lighted by electric lights, and is a narrow, crooked,

descending fissure, a _ganghöhle_, where the marks of water action are

plainly visible. At the bottom a little stream, evidently the active

agent in forming the cave, ran through the fissured limestone. In the

stream a large toad or frog was swimming about. There was nothing icy

about the cave or the water, and the temperature was normal. Ice was

never known to form in the cave. These two places, so close together,

are an interesting confirmation that it is only where the outside cold

can get in, that we find subterranean ice.

THE FREEZING CAVE AND FREEZING WELLS OF DECORAH.

Near Decorah, Iowa, is a freezing cavern, which is more frequently

referred to in cave literature than is generally the case. I visited it

on Friday, September the 30th, 1898, with an old English resident of

Decorah, Mr. W. D. Selby-Hill. The cave is situated about one kilometer

to the northward of Decorah, on the north bank of the Upper Iowa River,

at the base of a bluff. It is some thirty to forty meters above the

stream, and faces southward. It looks like a fault or fissure in the

rocks, with the sides meeting a few meters overhead. It is a true

cave, but probably in an early stage of formation, for there are no

apparent traces of water action, nor any stalagmites nor stalactites.

The absence of the latter may, however, be due to the fact that it is a

periodic glacière. The rock is a white limestone, rich in fossils. The

cave is some two to three meters in width and is rather winding, with a

short arm or pocket branching out on the west side. The main cave runs

back some thirty meters from the entrance. In one place it is necessary

to stoop, to get past some overhanging rock slabs. By candle light, we

went to the rear of the cave, and found it warm, dry, and free from

ice. There were no draughts, possibly because the day was cool.

[Illustration: ENTRANCE OF THE CAVE OF DECORAH.

From a Photograph by Mr. A. F. Kovarik.

]

I looked in vain for _tubular fissures_, or indeed any fissures,

through which _water might freeze by pressure in its descent_, as the

believers in the capillary theory say it does. Nothing of the kind

existed, and I wrote in my note-book: "Writing on the very spot about

which this theory was started, I feel justified in asserting that the

theory amounts to absolutely nothing and is entirely incorrect."

Mr. Hill told me that there were two wells in the southern portion of

Decorah Township, where ice was found in summer. I visited them both,

but found no ice, and the temperatures normal. Mr. Hill said that one

of the wells was dug about thirty years ago, and that the workman told

him that the ground which he went through was frozen; and that at one

place he struck an opening, from which came so strong a current of icy

air, that it was hard to keep at work.

I talked to several persons afterwards. _Inter alia_, they told me that

the bluff was a great place for rattlesnakes, sometimes big ones. They

admitted also generally that they were puzzled about the formation of

ice in the cave. Some claimed that the ice formed in summer--the old

story once more. I met, however, Mr. Alois F. Kovarik of the Decorah

Institute, who had made a series of regular observations for over a

year and found that the ice begins to form about the end of March and

beginning of April, and is at its maximum towards the beginning of

June. Mr. Kovarik also told me, that he had found ice in one of the

wells in the beginning of August.

This was an especially satisfactory trip to me, for it did away, once

for all, with any possible belief that there was any basis of fact for

the capillary theory. It also seems to me important to find that the

ice of these freezing wells melts in summer. For it shows that their

ice is due to the same causes as those which form the ice in the cave,

and is another proof against the validity of the glacial period theory.

FREEZING ROCK TALUS ON SPRUCE CREEK.

On Spruce Creek, Huntingdon County, Pennsylvania, about four kilometers

north of the Pennsylvania Railroad depot, is an ice bearing talus,

known locally as the Ice Holes or Ice Caves. I visited this spot, on

October the 5th, 1898, with Mr. Benner, of Spruce Creek. We walked

up the pretty valley along the old Pittsburgh turnpike, at one place

finding some papaw trees, whose fruit had a horrible sickening taste;

then we crossed Spruce Creek by a footbridge and followed the other

bank back for some five hundred meters, until we were nearly opposite

the old Colerain Forge, which is located in a piece of land called by

the curious name of Africa. About half way from the bridge we smelt

a strange odor, which my companion thought came from a copperhead or

rattlesnake: we did not investigate.

[Illustration: LOCUS GLACIALIS--CAVE OF DECORAH.

From a Photograph by Mr. A. F. Kovarik.

]

The freezing talus is situated at the foot of Tussey Mountain: it is

big, and is composed of small sandstone (?) rock débris. The talus is

at least thirty meters high and one hundred and twenty meters long.

As I stood at the bottom, I was reminded strongly of the talus at the

Dornburg. At the base were a number of small pits, evidently dug by

man. From the interstices between the rocks, icy cold draughts issued

in some places, and there was no doubt that there was plenty of ice

beneath the stones. In one place we thought we could see ice, and I

poked at the white substance with my stick, but I am not positive

that it was ice. All over the talus, the temperature was strikingly

colder than a few meters away, and in the pits we could see our breaths

distinctly. Although I am not much of a botanist, yet it seemed to me

that the flora immediately near the talus was somewhat different in

character from that of the surrounding country.

Mr. Benner told me that he saw, three or four weeks before, plenty of

ice in the pits; that they were made by farmers who formerly came to

this spot to get ice; and that parties occasionally picnic here in the

summer and make ice cream. He stated also that he saw, some years ago,

a small cave or hole containing ice near Mapleton, Pennsylvania, but

that it was destroyed by quarrying the rock away.

FREEZING GORGE NEAR ELLENVILLE.

On Sunday, October the 9th, 1898, with a young man from Ellenville,

I visited the well known Ellenville Gorge, in the Shawangunk Range,

Ulster County, New York. We left the hotel at eight-forty A. M. and

reached the gorge, known locally as the Ice Cave, at ten-five A. M.

It is about four kilometers northeast from Ellenville. The path rises

steadily uphill and is of the roughest description; it is covered with

loose stones, and looks as if it might become the bed of a mountain

brook in wet weather.

I call this place a gorge, instead of a cave, because it is uncovered

at the top, but probably originally it was covered. It is shaped like

a pit cave minus a roof, and it reminded me of the Friedrichsteiner

Eishöhle, and the Glacières de Saint-Georges and du Pré de

Saint-Livres. It is entered by a long slope from the western end, the

gorge turning northward further back. I estimated its width, at the

bottom at some five to seven meters, at the top at some three to four

meters; its length at some thirty meters and the deepest point we

reached, at some twenty meters below the surface. These are guesses,

however. In one place, a great rock slab overhangs the gorge. At nearly

the lowest point of the rock floor, there is a hole which extends

perpendicularly downwards some five or ten meters more; this opening

is partly blocked up with fallen masses of rock which would make a

further descent perilous. The north end of the gorge is also filled up

with a mass of great broken rocks; in fact, the whole place is out of

repair, as the rocks are cracked and creviced on both sides to a great

extent. The rock is friable and seems to be all breaking up, or rather

down, and I think there is some danger from falling stones, although

I did not see any fall. There is a good deal of moss on the sides of

the gorge, and on some ledges small evergreens are growing. The gorge

is sheltered thoroughly from winds by its formation and position, and

somewhat by the scrub forest surrounding it. There are several long,

deep crevices a few meters further up the mountain side, and I think

one of them is an extension of the main gorge.

[Illustration: GORGE AT ELLENVILLE.

From a Photograph by Mr. Davis.

]

We found no ice. It generally lasts till about the beginning of

September; and Professor Angelo Heilprin, and Miss Julia L. Lewis, of

Philadelphia, have found plenty of it in July and August. But the ice

had evidently now been gone for some time, for the temperature at the

bottom of the gorge was about 11° C. at ten-thirty A. M. This was but

little colder than the temperature v outside, which at ten-fifteen A.

M. was 14° C.

On returning to Ellenville, I learnt that there was another somewhat

similar smaller gorge, some eight kilometers away, at a place called

Sam's Point. This, however, is said to retain only snow, while in the

Ellenville gorge much ice is sometimes formed, and icicles a couple of

meters long are said to hang on the sides of the cliffs. The proprietor

of the hotel told me he had heard of a cave which contained ice not far

from Albany, at a place called Carlisle, on the Delaware and Hudson

Railroad.

FREEZING CAVE AND WINDHOLES NEAR FARRANDSVILLE.

I arrived at Farrandsville, Clinton County, Pennsylvania, early on

Tuesday morning, October the 11th, 1898, and found a boy, who worked

in a brick mill, as guide to the caves.[11] After emptying a small,

flat bottomed boat of the water of which it was half full, we rowed

across the Susquehanna River; then we walked up the road, along the

river bank, for a couple of hundred meters, and struck up the so-called

path to the caves. Although the whole of the mountain side was at the

disposal of the road maker, no better plan seems to have suggested

itself than to make the track go straight up. This saved making

zigzags, yet the result is that the path is steep, and as it is rocky

and slippery, it is hard travelling without bootnails or alpenstock.

[11] I learned of this cave from Mr. Eugene F. McCabe, of Renovo,

Pennsylvania. Mr. McCabe took out large pieces of ice from it in the

month of August. On December 23d, 1896, he found no ice inside the

cave, but a hoar frost covered the rocks; the temperature outside

was -5.6°; inside -4.5°: the day was clear and there was no breeze;

several matches lighted in the cave were almost instantly blown out by

a current of air coming from crevices in the rocks.

Mr. Ira C. Chatham, postmaster at Farrandsville, wrote to me on the

19th of October, 1898, as follows: "Your paper on Ice Caves [Journal

of the Franklin Institute, March, 1897] at pp. 177 and 178 describes

the Farrandsville Cave as near as is possible, as the ice forms in the

spring from the snow melting and dropping through the rocks into the

cave, and the rocks face directly north as stated."

As we went up, I noticed, in one or two places, cold draughts issuing

from crevices in the rocks. We soon came to a hollow under a rock,

where there were a number of cracks and crevices: the boy spoke of it

as the lower cave. It is some sixty meters above the Susquehanna River

and cold draughts flowed from the cracks, although we saw no ice. The

cave was about twenty meters higher up. One could crawl into it for

a couple of meters, and all round it the rocks are somewhat creviced;

in fact, I think there are a good many cracks in the entire hill.

There was no ice in sight in this hole, but a strong, cold draught

poured from it. After an exposure of fifteen minutes the thermometer

registered 6° C.; while outside, in the shade, it stood at 15° C. This

decidedly sub-normal temperature proved unmistakably, in my opinion,

the presence of ice a little further than we could see in. Both holes

face about north and are sheltered, by their position and by the sparse

forest which covers the ridge, against all winds except those from the

north.

I talked to the postmaster and the railroad agent at Farrandsville

on my return, and they stated that there was no ice in the hole in

winter, but that it formed about April and remained over until towards

September, showing that the cave is a normal glacière on a small scale.

GLACIÈRES NEAR SUMMIT.

In the search for coal, the mountains of the Appalachian Chain between

the little town of Summit, and the neighboring village of Coaldale,

Carbon County, Pennsylvania, were mined and tunneled in every

direction. Owing to the caving in of some of these mines, depressions

formed in certain places along the ridge in the upper surface of the

ground, and in two of these hollows natural refrigerators occur. These

were brought to my notice by Mr. C. J. Nicholson of Philadelphia, and I

visited them on May the 5th, 1899, in company with two coal miners of

Summit.

Starting from Summit, we passed across some rough ground under which

there was a mine on fire; and the miners showed me the tops of two

pipes sticking out of the ground, from which issued a smoke or steam,

too hot to hold the hand in more than a few seconds. Going beyond

through brushwood, for a couple of hundred meters, we came to the

first glacière, which was also the nearest to Summit. It faced almost

due north and looked as if it was formerly the entrance to a mine. It

was fairly big, and my companions assured me that, until within about

a year, ice was always found in it. Recently, however, part, of the

rock roof fell in, blocking up the entrance with a mass of débris and

making it unsafe to venture in. Formerly parties of tourists constantly

visited this place, after coming over the Switchback, but this is no

longer done and there has been some talk of cleaning away the broken

rocks and making the glacière accessible. The men also said that

occasionally people living in the neighborhood had dug out the ice for

their own use.

The other glacière was a short distance further, in the direction of

Coaldale. It is in a pit, which may have been the mouth of a disused

shaft or only a depression resulting from a cave-in. A scrubby forest,

which surrounds the hollow, acts as a windbrake. A rather steep slope

leads down into the pit, and at the end passes under the wall of rock

of the opposite side for a short distance, forming a small cave, which

faces almost due south and whose floor is choked up with broken rock

fragments. At the bottom of the slope we found some snow, and among

the boulders a good deal of snow-ice as well as several long icicles

hanging from the rocks. All the ice and snow lay on the north side of

the rocks, or underneath them, so that it was in shady places where the

sun could not reach it. The temperature was not at all uncomfortable,

although somewhat cool and damp.

[Illustration: Fig. 9. Vertical Section of Pit near Summit.]

There was nothing in either glacière, to show that the ice was formed

from any other cause than the drifting in, and melting and refreezing

of the winter's snow; and my impression is that the ice in the second

glacière could not last through the summer.

THE SNOW HOLE NEAR WILLIAMSTOWN.

The Snow Hole near Williamstown (Massachusetts) is situated near the

northern end of the Petersburgh Mountain of the Taghconic Range; it is

slightly below the watershed on the Williamstown side, at an altitude

of about seven hundred meters. The Snow Hole is in the State of New

York, near the boundary between New York and Massachusetts. It is a

long two hours' drive from Williamstown, the last four kilometers

or so, over an exceedingly steep and rough road, which is, in fact,

nothing but an old logging road, and the worst I ever drove over except

the road to Démenyfálva.

I visited the Snow Hole with my brother on Friday, September the 29th,

1899. It is surrounded by a dense forest, mainly of recent growth,

which thoroughly shelters it from all winds. In shape and appearance

it resembles the Gorge at Ellenville, except that it is smaller: its

location on the ridge is not unlike that of the Friedrichsteiner

Eishöhle. It is a narrow crack--or cave minus a roof--about fifteen

meters long, six to seven meters deep and from two to five meters wide.

It faces nearly north, and the bottom is in perpetual shadow. From the

northern end, a gentle slope leads to the rear. The slope was a good

deal blocked up by a big tree with large branches, which had fallen

directly into the fissure. There was some moss or greenish mould on

the rocks in places, and at the rear end of the slope there were

some fissures in the rocks, into which one might perhaps have crawled

a little farther, which formed a tiny cave. There was also a similar

incipient cave at the northern end. I could not detect any draughts

issuing from these rock fissures, and the air throughout was still,

although the wind was blowing hard on the ridge. The rocks were moist

in places and the air damp, but there was neither snow nor ice and the

temperatures were normal. The driver told me that he had found plenty

of snow in the base of the gorge some years ago in July; and he said

that he had always heard that snow was found in the Snow Hole all the

year round. All the conditions of the place, the shape of the fissure,

and its sheltered northern exposition, are favorable to the retention

of ice and snow, and it is not surprising that they remain over every

spring.

ICY GULF NEAR GREAT BARRINGTON.

The Icy Gulf or Icy Glen is some eight kilometers from Great

Barrington, Massachusetts. I have not been in it, but was told in

October, 1899, by the farmers living near by, that after snowy winters,

ice remains over through July. It must be similar to the Icy Glen at

Stockbridge.

THE ICE BED OF WALLINGFORD.

The Ice Bed of Wallingford is situated about three kilometers to the

east of Wallingford, Vermont. A drive of half an hour, over the Mount

Holly and Hearburrow roads, takes the visitor to the entrance of a

rough wood path, which, at a distance of three or four hundred meters,

leads to the Ice Bed. This is a huge talus, at the base of the White

Rock Mountain, whose cliffs rise steeply overhead for some three or

four hundred meters. The talus, which was doubtless formed by a great

slide at some distant date, consists of granite boulders, some of which

are big ones. The ice-bearing portion may be some thirty or forty

meters high vertically. It lies in a sort of gully or rock basin, and

at the top is about thirty meters broad, tapering to a point at the

bottom. The talus faces southward, and during a good part of the day

the sun shines full upon it. A thin forest fringes the sides and grows

round the bottom, but this can afford but little protection from the

winds, especially to those from the south.

I visited this place on the 5th of October, 1899. There was a distinct

drop in temperature as we neared the base of the talus, and a cool air

drew gently down over the rocks. I think slight draughts issued from

some of the crevices; but of this I am not sure. The temperature was

sub-normal, about 8°, but hardly low enough to prove the presence of

ice, although we could see our breaths distinctly. We looked carefully

under a number of the boulders, but neither ice nor snow was visible.

I was assured that ice was abundant there in the past July and August,

and I should think it had melted away only shortly before my visit. My

impression is, that this is a periodic glacière.

CAVES NEAR WILLIAMSTOWN.

On the eastern slope of the Petersburgh Mountain of the Taghconic Range

in Massachusetts, at a good deal lower altitude than the Williamstown

Snow Hole and about southeast of it are some caverns, which are but

little known. A five or six kilometer drive from Williamstown takes the

visitor to the base of the mountain, whence a rather steep ascent of

about a kilometer and a half brings him to the caves, which are in the

midst of a dense, scrub forest.

The caves were first entered, and possibly discovered, by Mr. W. F.

Williams, of Williamstown, when a boy. Since then, he has visited them

many times and explored them a good deal. They do not appear to have

any name as yet, and it would seem only fitting to christen them after

their explorer: the Williams Caves.

There are several unimportant holes in the immediate neighborhood of

the two main caves. The latter lie side by side. The rock formation is

the same as that of the Snow Hole, a dark gray slate with a few veins

of quartz, and they are due also evidently to the same geological

causes. It would seem as though the mountain had tended to open or

crack at these spots and fallen apart. This seems probable, because

wherever there is a projection on one side of the cracks, there is a

corresponding hollow in the opposite side. After this, water action has

come, and erosion and corrosion have worn out and carried away earthy

matter, and slowly deepened and widened the fissures. The remarkable

point in connection with the main caves, however, is that one is a

normal cave and the other a periodic glacière.

I went with Mr. Williams to these caves on the 6th of October, 1899,

and partially explored the glacière. On the way up, just as we left the

carriage road, a fine, three-year-old buck, in his winter coat, came

bounding out of the forest; on seeing us he stopped, and after taking a

good look, quietly trotted off into the bushes.

The glacière is rather peculiar in shape and may be described as two

storied. A long slope, set at an angle of some forty degrees, and

covered with mud and dead leaves, leads down into the crack, which

is from one to three meters in width. The first half of the slope is

open to the sky; the last half is covered by the rock roof, and is a

real cave. In this the floor is horizontal, the place forming a little

chamber in which the daylight has almost vanished. At the exact summit

of the slope a big tree grew most conveniently; and we tied to this one

end of a twenty-meter Austrian Alpine Club rope, and by holding fast

to it, and kneeling or sitting down in the mud in two or three places,

the descent was easy enough. It was rather difficult to scramble up the

slope again, however.

[Illustration: Fig. 10. Vertical Section of Freezing Cave near

Williamstown.]

In the floor of the little chamber there are two holes, and, stepping

over these, we stood at the rear end, about eighteen meters distant

from the beginning of the slope. My companion now set some birchbark

on fire and dropped it into the innermost hole, and we laid down in

turn, flat on the rock floor, and craned our necks through the hole.

Mr. Williams thought he could see ice below us. I looked down after

him and found that I was looking into a lower chamber whose sides were

invisible. The floor was some three meters below vertically, and on

this the birchbark was burning brightly. I think I saw some ice, but

I could not be sure, as there was too much smoke to see distinctly.

My companion offered to go down through the hole and get some ice; a

proposition I promptly vetoed, as had anything gone wrong, I could not

possibly have given him any assistance, as there was no extra rope.

Mr. Williams told me that he went down several times before in July or

August, and always found ice on the slanting floor. He said he did not

know how far this lower chamber extended, nor the length of the ice

floor. One thing which makes me hesitate to think that we saw ice was,

that the temperature of the chamber where we were was not at all icy;

but probably--I had forgotten my thermometer--nearly normal.

When we stood once more by the tree at the top of the slope, the mouth

of another cave was visible about two meters below us. Mr. Williams

said it had never looked more than a little crack before, and that the

opening was much bigger than at his last visit. It was directly under

the slope by which we descended and it vanished into darkness. Its

direction led straight towards the lower chamber, and it almost surely

leads to it. It seems thus that there are two hollows, one directly

above the other; and that the lower one is a glacière, while the upper

one is not. The cold air of winter would naturally sink into the lower

chamber, and the spring thaws would furnish plenty of drip, so that

this place seems to answer every requirement of a cave glacière.

But the most interesting fact about these caves is that, while the

shallower one is a glacière, the bigger and deeper one is not. This

is situated about ten meters north of the glacière and the direction

of the entrance is about the same. Mr. Williams has found snow and

ice in May in the entrance pit as far as the daylight goes, but none

beyond. I am inclined to think that the explanation of this is the fact

that the cave is a _ganghöhle_ or tunnel cave. Mr. Williams described

it as a narrow passage with chambers, and at least a hundred meters

long, and fifty meters in depth below the surface. The cold air sinks

in a certain distance, but as the passage is narrow and long, and too

winding for any strong draughts, the cold air which enters is soon

neutralized by the supply of warmer air within and by contact with the

rocks. I cannot help thinking that it is by some such explanation that

we must hope to solve the problem of why certain caves are glacières

and others in the immediate neighborhood normal caves; and the caves

near Williamstown are exceptional in presenting the problem so

patently.

PART II.

THE CAUSES OF SUBTERRANEAN ICE.

THE CAUSES OF SUBTERRANEAN ICE.

I.

_Terminology._--Ice enduring the entire year is found, in temperate

latitudes, in a variety of forms and in several different kinds of

places. In some cases it is entirely above the surface of the earth;

in others it is entirely beneath the surface of the earth. These are

the extremes, and between them there are certain intermediate forms.

The perennial ice above ground of temperate regions has gradually

become known in English by the French word _glacier_, but strange to

say, there is no term in use in English which accurately describes the

perennial ice formations which are partially or completely underground.

Thus the term "ice cave" is applied to a rock cavern containing ice,

and the term "ice gorge" to a rock gorge containing ice. Both terms

are misleading, because the character of the contents is mentioned

before the nature of the geological formation. We say correctly enough

"limestone cave" or "lava cave" and, in my opinion, we should apply the

term "ice cave" in a similar manner to the hollows in the ice at the

lower end of glaciers, whence the glacier waters make their exit. These

are really "ice caves," that is caves with sides and roof made of ice.

Another trouble of the term "ice cave," as applied to rock formations

containing ice, is that it is not generic: not only is it incorrect,

but also it is not comprehensive. It does not apply to mines, tunnels,

wells, gullies, boulder taluses, or underground ice sheets. If "ice

cave" is used, except in its true sense of glacier ice cave, it seems

at least as though it should be so only for real caves which retain

ice, as opposed to taluses and wells. Curiously enough, the Germans

are just as inaccurate as ourselves, for their terms _eishöhle_

and _eisloch_ are absolute translations of our "ice cave" and "ice

hole." Indeed, there is no doubt that some of the incorrect notions

about subterranean ice formations, are due to the inaccuracy of the

terminology.

The only language, so far as I know, which has a correct and really

generic term for subterranean ice formations, is the French in its word

_glacière_. The French and Swiss say _glacières naturelles_ of ice

deposits formed naturally underground; and _glacières artificielles_

of ice houses. _Glacière naturelle_ is comprehensive and accurate. It

covers all the rock formations and suggests also the mode of formation

of the ice. It likewise implies the strong resemblance between natural

ice deposits and artificial ice houses. It might be well, therefore,

if the French term _glacière_ were adopted as a generic term for all

underground ice formations. As, however, there is little likelihood of

this happening, the question arises as to the best English equivalent

or equivalents. These seem to be "freezing cavern, freezing talus,"

etc., "natural refrigerator" or "subterranean ice formation." "Natural

refrigerator" and "subterranean ice formation" are more generic than

"freezing cavern, freezing well," etc.; but the latter have the

advantage of suggesting immediately that reference is made to the

hollows of the earth which at times contain ice; and, therefore, they

are the best terms, perhaps, which can be chosen in English.

Another point in the terminology of this subject has reference to

subterranean hollows where draughts issue or enter. Such hollows are

found in all parts of the world and are known usually in English as

"blowing caves" or "cold current caves." The Germans speak of them as

_windröhren_ or _windlöcher_. In my first paper about caves,[12] I

used the word "windhole" which I translated from the German. The term

"windhole" seems to me preferable to "blowing cave" or "cold current

cave" in that it is more generic. It applies to taluses or boulder

heaps, or in fact, to any hollows where draughts issue or enter,

whether these hollows are genuine caverns or not.

[12] _Ice Caves and the Causes of Subterranean Ice_, November 1896, and

March 1897.

It is necessary also to explain here that "glacière" and "windhole" are

not synonymous terms. It must be understood that a glacière or natural

refrigerator is a place where ice forms and endures in a subterranean

or semi-subterranean situation; and that _the presence of ice_ is the

criterion of whether a place is or is not a glacière. Likewise it must

be understood that a windhole or blowing cave is an underground hollow

with at least two openings, and in which distinct draughts occur; and

that the _presence of draughts_ is necessary to constitute a place

a windhole or blowing cave. A freezing cavern may or may not be a

windhole, and a windhole may or may not be a freezing cavern.

_Temperatures._--The phenomena of glacières are so closely connected

with temperatures that it seems necessary at this point to mention

some general facts in connection with subterranean temperatures, even

if these still form a subject of some uncertainty, and one about

which further observation is desirable. Subterranean temperatures may

be grouped under three heads: 1, Ordinary or normal temperatures;

2, Temperatures above the normal or super-normal temperatures; 3,

Temperatures below the normal or sub-normal temperatures.

1. In the great majority of caves, cellars and subterranean places

of all descriptions, the temperature of the air is about the same,

all the year round, as that of the ground. The frost of winter and

the heat of summer penetrate the earth for some trivial distance, a

few meters perhaps, and lower or raise the temperature of the ground

temporarily. Below this there is a stratum where the temperature is

found to vary but little the entire year and which, in a majority

of cases, approximates the mean annual temperature of the district.

Below this invariable stratum, the temperature generally rises

slowly, not at exactly the same rate everywhere, but in a regular

increase. This increase of temperature averages 1° C. for every 32

meters. As most caves and cellars are of small depth and as they take

their temperatures from that of the ground, it follows that as a rule

their temperatures are moderate and pleasant. And as the air of the

majority of caves and subterranean hollows is about the same as the

temperature of the surrounding rock, it is correct to call subterranean

air temperatures closely approximating the ordinary temperature of the

ground, ordinary or normal temperatures.

As already stated, with an increase of depth, there is, in almost all

cases, a regular increase of temperature. For this reason, mines, which

are much the deepest hollows reached by man in the surface of the

earth, are, as a rule, warmer in the lower levels: if deep, they are

also hot. And this is so generally the case that warmer temperatures at

the bottom of mines may be considered as normal.

2. In a few hollows close to the surface, there are temperatures much

above the normal temperature of the ground. Such places are rare and

abnormal.[13] The heat is generally due to the presence of hot springs

or to some volcanic action in the immediate neighborhood. In the case

of one cave close to the surface, the heat is due to some limekilns

which are situated immediately overhead.[14] Where these warm hollows

are genuine caves it seems proper to call them "hot caves."

[13] Kraus. _Höhlenkunde_, page 86.

[14] Grotte du Jaur. _Les Abimes_, page 160.

3. In a number of places, there are abnormally low temperatures

underground either for the whole or only for part of the year.

Although commoner than hot caves, yet the underground places with low

temperatures are also rare and abnormal. They may be divided into two

groups: 1, Those where the temperatures are lower than the normal,

without becoming low enough for ice to form; and 2, Those where the

temperature sinks so low, that ice forms.

It is difficult to make definite divisions among the various forms of

natural refrigerators, but it is correct, probably, to classify them

under five heads, in accordance with the different kinds of formations

of the hollows in the rocks:

1. Gullies, gorges, and troughs where ice and snow remain.

2. Soil or rocks overlaying ice sheets.

3. Taluses and boulder heaps retaining ice.

4. Wells, mines and tunnels in which ice sometimes forms.

5. Caves with abnormally low temperatures, and often containing ice.

1. _Gorges and Troughs._--Gullies, gorges and basins which retain snow

and ice are fairly numerous in mountain districts. They are generally

ravines, or rock fissures, or hollows, in positions below the snow line

where snow and ice are sufficiently protected, from sun and wind, to

remain long after snow in the surrounding open country, at the same

altitude, has melted away. Some of these gorges are small, some big. As

a rule, they are deep and narrow.

In north-eastern Siberia, a form of permanent surface ice is found,

which the Tungusses speak of as _tarinnen_, which means "ice troughs"

or "ice valleys."[15] These _tarinnen_ are broad valleys, with either

a horizontal floor or one sloping gently in the form of a trough, over

which the ice is spread in the form of a sheet. The Tungusses assert

that the ice in some of these troughs never wholly melts away, although

it lessens in quantity from the beginning of May till the end of

August, after which it once more increases.

[15] _Bulletin de la classe physico-mathématique de l'Académie

Impériale des Sciences de St. Pétersbourg._ 1853. Vol. XI, pages

305-316.

_Subterranean Ice Sheets._--In several places in different parts of

the world there are underground ice sheets which extend over large

spaces; they are common under the tundras of Alaska; and there are fine

examples on Kotzebue Sound,[16] on the Kowak River,[17] and along the

Yukon River.[18] The "Ice Spring" in Oregon seems to be a formation of

the same kind. Several examples of these subterranean ice sheets are

reported also from different parts of the Russian Empire.

[16] See Part III: page 167.

[17] See Part III: page 167.

[18] See Part III: page 166.

A somewhat different kind of ice sheet was observed on Mount Etna. Sir

Charles Lyell[19] speaks of it as a "glacier preserved by a covering

of lava." He says Signor Mario Gemmellaro satisfied himself that

nothing but a flowing of lava over snow could account for the position

of the glacier. Ice sheets somewhat similar to these are reported

from Tierra del Fuego,[20] and probably also such sheets occur in

Iceland; and enormous heaps of ice covered with sand are found on Mount

Chimborazo.[21] On the northwestern coast of Greenland, glaciers, whose

flow has stopped, were observed buried under an accumulation of moss

and grass.[22]

[19] _Principles of Geology_, 11th Edition, Chap. XXVI.

[20] See Part III: page 190.

[21] See Part III: page 189.

[22] See Part III: page 165.

_Taluses and Boulder Heaps._--Taluses and broken debris, and in general

boulder heaps of all sorts, have interstices and openings between the

boulders, and in these it occasionally happens that ice is found. This

is most common among the taluses at the base of cliffs, but in some

cases ice is found among broken rocks on the sides of gently sloping

hills, or even on the plateaus of their summits. Sometimes the ice

and snow on the bottom of rock gorges all melts away, while further

down, in the hollows of the boulders forming the floor, ice still

remains. The rocks of which these ice bearing taluses are formed are

generally gneiss, granite, limestone, sandstone, basalt or porphyry.

Among such boulder taluses the phenomenon designated as _Windröhren_

or _Ventarolen_, that is, windholes, is frequently found. Sometimes

the air among such boulder formations is quiet, but as a general thing

draughts pour out at the lower openings during the hot months, and blow

into them during the cold ones.

_Freezing Wells, Mines and Tunnels._--Subterranean ice is also found in

certain places in connection with man's handiwork. In a few wells in

the United States, the temperature in winter becomes abnormally low,

and for four or five months these wells freeze up and become useless.

A case of a freezing well was recently observed near la Ferté Milon in

Central France.[23] Ice is reported also as forming in various mines in

Europe, Asia and America; in fact, it is not an uncommon occurrence.

Occasionally, also, ice forms in tunnels.

[23] See Part I.: pages 74, 79, 89. Part III.: page 206.

_Cold Caves._--Caves with abnormally low temperatures may be divided

into two classes. First, caves where the temperatures are lower than

the normal, without becoming low enough for ice to form; and second,

caves where the temperatures sink so low, that ice forms.

Caves where the temperatures sink below the normal, but in which ice

does not form either in winter or in summer, are found in several

places in different parts of the world. They are termed in French

_cavernes froides_ and in German _kalte höhlen_. There are but few data

from reliable observers about such cold caves. Some descriptions are

given without thermometric measurements, and the statements that the

caves are cold, mean nothing beyond the fact that they feel colder than

the outside air. It is, however, conclusively proved that cold caves

exist, and that while they are not freezing caverns, yet that they have

a temperature lower than the mean annual temperature of their district.

In fact, the assumption, which had passed into an axiom, that caves

always have the same temperatures as the mean annual temperature of

the district, must certainly be given up. Cold caves are generally in

one of two shapes: 1, in the shape of a sand glass,--two cones above

each other meeting at the narrowest point--where the upper cone lets

the heavy cold air descend easily, while the lower bell shaped cone

prevents its escape; and 2, where two sink holes open into one pit,

which is in the shape of a bell.[24]

[24] _Les Abimes_, page 563.

_Glacière Caves or Freezing Caves._--Caves where the temperatures

sink so low that ice is able to form, are found in many different

rock formations and in various positions, shapes and sizes. The rock

formation of freezing caverns is generally limestone, but sometimes it

is marble, lava, basalt, gneiss or granite. In all cases, however, the

rock is either porous or else it is broken and fissured, as otherwise

the water supply necessary to the formation of ice could not find its

way in.

Glacière caverns may, for the sake of convenience, be classified into

several classes, according to their position or to their form. The

lines of transition between them, however, are so indefinite in nature,

that it is often difficult to specify a cavern as belonging to any

special type. The most important factor in classifying glacière caves

is their position. Under this head there are two main divisions: first,

pit caves; second, cliff caves.

Pit caves are those where a pit or pits open into the ground, and the

ice is found at the bottom. Sometimes there is no roof, when the place

may be called a gorge: this occurs at Ellenville, where the roof has

fallen. Again, the pit itself is more or less roofed over and the ice

is found mainly or wholly under the roof: this is the case at Haut

d'Aviernoz, at the Friedrichsteinerhöhle, at Saint-Livres, and at

Saint-Georges. Sometimes the pit takes the form of a descending tunnel,

leading into a hall or chamber, in which the ice lies under a rock

roof: this happens at Chaux-les-Passavant. In all these pit caves the

body of the cave is below the entrance, and most of them are fairly

well lighted by daylight throughout. Generally there is only one pit,

but occasionally there are two connected underground, as is the case at

La Genollière.

Cliff caves are those where the entrance is at the base or in the

side of a cliff. Frequently the cave is in the shape of a hall or

chamber, which begins directly at the entrance, and which may be large

or small. This kind always has a down slope directly from the mouth.

The Kolowratshöhle, Dóbsina and the Grand Cave de Montarquis may be

mentioned as examples. In some cases there is a pit at the base of

a cliff and there is a slope leading down to the cave, somewhat in

the form of a tunnel: this is the case at Manchester and practically

also at Roth. Again there is a more or less long gallery between the

entrance and the glacière, which is always below the level of the

entrance. The Schafloch, Démenyfálva and Decorah may be cited as

examples. As a rule the gallery slopes down from the entrance, but

sometimes the floor rises and then sinks to the glacière. The top of

the entrance, however, is always higher than the highest point of the

floor, as otherwise the cold air could not get in. This is the case at

the Frauenmauerhöhle, and, apparently, also at the Posselthöhle. In one

case, at Amarnath in Kashmere, the floor is said to rise to the roof at

the back; but as the entrance is nearly as big as the floor area, the

ice formations must also be below the level of the top of the entrance.

The dimensions of glacière caves vary greatly. Some are large, others

are small. Saint Georges, a roofed pit cave, is some twenty-five

meters by twelve meters, with a depth of about twelve meters.

Chaux-les-Passavant, a cave at the end of a pit tunnel, has a diameter

of some twenty-seven meters. The measures of Dóbsina, a cave at the

bottom of a cliff, are given as follows: Height of roof above ice

floor, 10 to 11 meters; length 120 meters; breadth, 35 to 60 meters,

and surface about 4644 meters. The Frauenmauerhöhle is a gallery about

one hundred meters long before the ice floor is reached, and this is

some fifty meters more in length by about seven meters in width. The

glacière cave near Frain, on the contrary, is so small that one can

only crawl in some two or three meters. In fact, glacière caves vary in

size between great halls and little tunnels where one cannot stand up

straight.

The entrances of glacière caves also vary greatly in their dimensions.

For instance, the Friedrichsteinerhöhle is on one side of a huge pit

and is as large and deep as the pit. Saint Georges, on the contrary,

has, near one end of the roof, a couple of holes, some three meters in

diameter. The entrance to the Schafloch is four meters wide by four

meters seventy centimeters high, while the entrance to Roth is not over

one meter each way.

A classification of subterranean ice formations, and one which applies

to all the different forms, is into permanent and periodic glacières.

When in any underground spot, ice remains throughout the year, the

place may be called a permanent glacière; when on the contrary the ice

melts away for part of the year, the place may be called a periodic

glacière. This classification, which several observers have used

already, is convenient and valuable.

_Movements of Air._--Another classification of glacières can be made

in accordance with the movements of air underground. Glacières may be

divided into those where there are no strong draughts in summer and

those where there are draughts: or into "apparently static caves"; and

"dynamic caves" or "windholes." The first class includes those caves

where there is one or more openings close together and those above the

body of the cave. In such hollows the air in summer is nearly still,

while in winter there are distinct rotary movements of the air as

soon as the temperature outside is lower than that within. Almost all

glacière caves belong to this class of caves without strong draughts

in summer. Sometimes, however, ice is found in hollows where there are

two or more openings, at different altitudes and at different ends of

the hollow, and where there are draughts. Occasionally, also, there are

fissures in the sides or rear of apparently static caves, which allow

something like draughts at times, as is the case at the Grand Cave de

Montarquis.

Professor Thury of Geneva coined the terms "static cave" and "dynamic

cave" which have come largely into use since, and which practically

correspond to the German terms _eishöhle_ and _windröhre_. I do not

think the term "static cave" accurate, and prefer the term "apparently

static cave" or "cave without distinct draughts." For although there

are many caves where the air seems stagnant at times, and there are no

distinct perceptible draughts, still that the air is really stagnant

all summer appears to me doubtful, and it seems as if the movements of

air were distinctly apparent only in certain caves and not in others.

Air which is apparently stagnant is found in both pit and cliff caves

mainly in the summer months, but even in these I have noticed several

times in summer slight movements of air, especially near the entrance.

I could not exactly feel the air moving, but by lighting a cigar the

smoke could be seen borne outwards exceedingly slowly. At the entrance

of the Kolowratshöhle I think there was a faint outward current when I

was there. The day was hot and windless, and as the cold air met the

hot outside air it formed a faint cloud or mist at the mouth of the

cavern. At Saint-Georges, although the air seemed tranquil, I found

that the smoke of my cigar ascended rapidly just below the hole in the

roof, showing an ascending air current. In the double cave of Chapuis,

I found one cavern filled by a little lake over which there was a

draught.[25]

[25] See Part IV.: Butler, page 308.

From the few winter observations we have, there can be no doubt that in

winter the movements of the atmosphere are lively, the break in the air

column occurring as soon as the outside temperature is lower than that

within, when the outer air immediately begins to sink into the cave.[26]

[26] See Part III.: Chaux-les-Passavant, page 203; Saint-Georges, page

220.

If I have doubts as to the existence of absolutely static caves, it is

different about dynamic caves. When a subterranean hollow goes through

rocks, with one opening higher than the other, there will surely be

distinct draughts. These dynamic caves exist in many parts of the world

under such names as cold current caves or blowing caves or windholes.

Sometimes they are fissures in broken limestone. Often they are the

cracks between piles of boulders. A cool air generally pours from the

lower opening in summer while the cold air pours into it in winter, the

draught being then reversed. At the upper opening the operation takes

place in the opposite way, the hot air being sucked in in summer, and

given out in winter. Sometimes, however, changes take place, according

to the differences in the outside temperature, in the direction of the

air current in the course of a single day.

The causes of the movements of air in these windholes are exceedingly

simple. The movements of air depend on the fact that in summer the air

in the tube becomes colder from contact with the rocks and, therefore,

heavier than the air outside, and by gravity the heavy inside air

displaces the lighter outside air and comes rushing out at the lower

opening. This leaves a vacuum, which is filled by the warmer air

dropping into the tube from above. In winter on the contrary, the air

within the tube is warmed by contact with the rocks and becomes lighter

than the air outside. It, therefore, rises and streams out from the

upper opening, and the vacuum is filled by the heavy cold air pushing

in at the lower opening.

[Illustration: Fig. 11. Vertical Section of a Windhole.]

G. F. Parrot's[27] explanation is so satisfactory that I give it with

one or two changes. He considers the air movements an ordinary statical

phenomenon of the air, in caves which have two openings at different

altitudes. Let E G D represent the section of such a cave with the

openings A and B. Let us think that there are over C and B two vertical

air columns and from B to C a horizontal air column B C; then the two

air columns over B and C are at all times of the year equal in weight.

Not so the air columns A C and A E G D B, because their temperatures

are different. Assume the temperature in the cave G is +12° the whole

year round. If in summer the air column A C is at a temperature of

+25°, then the heavy air in the cave G pours out through A and is

replaced by air flowing in through B. If in winter the air column A

C is at a temperature of -1°, then the air pours with equal inverse

velocity at A into the cave, and out at B. The velocity of the current

in both cases depends on the difference of temperature within and

without.

[27] _Grundriss der Physik der Erde und Geologie_, 1815, pages 92-99.

The foregoing explanation makes it evident that the movements of air

in these windholes do not depend on the presence of ice. In many of

those I have examined myself there was no ice visible, and from the

temperature of the air current, there could not have been any ice

within the mountain. Still, there are numerous cases where ice is found

in windholes among boulders, and a few cases where windholes exist in

connection with apparently static glacière caves. Undoubtedly the great

majority of windholes do not contain ice in summer, or, indeed, at any

time of the year, and, as far as I can see, windholes, according to

their temperatures, belong rather to the class of normal caves than to

that of glacières.

_Forms of Ice._--Almost all the forms assumed by underground ice are

different from those assumed by overground ice. This is not surprising,

as the conditions, under which the ice is formed, are so different.

Almost all the lines of underground ice are rounded. The sharp angles

and fractures visible on glacier or iceberg are absent. Instead of

seracs and crevasses, broken ice falls, or piled up ice floes, we have

hanging stalactites and rising stalagmites, smooth ice floors and

curved ice slopes. This difference is of course due to the fact that

most subterranean ice is formed from the drip from the roof or the

sides of caves, and because the factor of motion--which plays so large

a part in the shaping by fracture of overground ice--is practically

wanting.

The most striking forms of subterranean ice are the ice stalactites

and stalagmites. They descend from the roof as icicles or rise from it

as rough cones or pyramids. The icicles are of all sorts of shapes and

sizes: sometimes they are tiny; sometimes they grow downward till they

reach the floor and form regular columns, in some cases no less than

eleven meters in height.

The ice stalagmites likewise are of all sorts of shapes and sizes, some

of them growing to a height of seven or eight meters. Occasionally they

have hollow bases, but this is rare. How these hollow cones are formed

is a still uncertain matter; but it is in some way by the action of

the drip. At the Kolowratshöhle I saw the drip from the roof cutting

out in July the basin, whose tall remaining sides suggested that early

in the spring it was probably a hollow cone. The cone at the Schafloch

of which I saw one half remaining, could only be accounted for by

some action from the drip.[28] The warmth of the rock floor may help

perhaps also, in melting away some of the base of the hollow columns.

[28] See Part IV.: Thury, page 287; Browne, page 290.

The frozen waterfalls which issue from fissures in the rock walls of

caves are another form of ice seen only below ground. For lack of a

better name, I call them fissure columns. A peculiarity of these is

that, while the rock fissure is more or less rectangular or at least

sharp angled, the ice column issues in a rounded stream. Sometimes

these fissure columns stream over the rock; sometimes they spring out

far enough from the rock to be quite away from it. They vary from about

one to five meters in height, and at the base they almost always spread

out in a shape resembling that of a fan.

The ice on the bottom of caverns of course takes its shape from the

form and angles of the floor of the caves. If the bottom is level or

nearly so, the ice lies on it as a sheet or floor. If the bottom of the

cave is sloping, the ice follows the angles of the slope, forming an

ice slope or ice wall, and sometimes becoming nearly or quite vertical.

These ice slopes distantly resemble the portions of glaciers called

an ice fall, with the great difference, however, that there are no

crevasses, not even tiny ones.

Occasionally, slabs of ice are found reposing in a fractured sheet over

a solid ice floor. This means that a lake has formed on this spot in

the spring, frozen over, and then run off, leaving its frozen surface

in broken pieces on top of the under ice.

Another kind of frozen water is the hoar frost which forms on the

rock roofs and walls. This is not at all rare. It is an open question

whether this is not the same thing as that which has been described as

subterranean snow.[29] I found myself in Dóbsina a small sheet of what

to look and touch was snow. I wrote of this as snow in my first paper

about glacières[30], but I am of the opinion now that it was the hoar

frost detached from the roof and not genuine snow.

[29] See Part III.: Ziegenloch, page 247; Creux de Souci, page 207.

[30] _Ice Caves and the Causes of Subterranean Ice_, November, 1896,

and March, 1897.

At Dóbsina, also, I noticed that the ice of the ice wall of the

Korridor assumed a stratified or laminated form. Mr. John F. Lewis

of Philadelphia suggested to me that this was probably due to a

precipitation of the hoar frost from the roof, and I think his

explanation is correct. The hoar frost forming at a certain degree of

cold, would doubtless be precipitated at a rise of temperature, and

would then act much as do the different layers of snow in the upper

portion of glaciers.[31] It would consolidate gradually, layer over

layer, and form strata, producing the banded or laminated structure

visible in the vertical ice of the Dóbsina Korridor.

[31] Whymper: _Scrambles amongst the Alps_, 1871, page 426.

The ice in caverns is sometimes found with a structure which is, I

believe, of rare occurrence above ground. This is when it takes the

shape known as prismatic ice, which means that if a lump is broken

from a column or icicle, the fracture will show regular prisms. This

phenomenon is not as yet satisfactorily accounted for; the only thing

certain about it is, that it does not occur in ice of recent formation.

From my own observations, I should say that ice became prismatic at the

end of summer; at least I have always found it in August or September

rather than in June or July.[32]

[32] See Part IV.: Browne, page 289; Lohmann, page 303.

Besides building up ice heaps, the drip, also, has the function of

destroying its own creations. If there are no crevasses, there are

holes and runnels. These are generally found at or leading to the

lowest point of the ice floor. Occasionally the holes are deep,

sometimes many meters in depth. They are certainly cut out by the

melting water, to which they offer an exit; in fact they are a part of

the drainage system present in all glacière caves, where there must be

some outlet for surplus water at or near the lowest point: and as the

caves are always in porous or broken rock, the drainage takes place

through the cracks and fissures.

The drip produces also the exact opposite of pyramids in the shape of

ice basins. These are cut in the floor by an extra strong drip from

the roof at those spots. Basins exactly like these are not seen on

glaciers. Not infrequently they are full of water of considerable depth.

Lakes and pools are found in glacière caves. Sometimes they are on

the ice floor, and in this case they are due either to rain-water

collecting faster than it can flow off, or else because the cave is in

a state of thaw. Sometimes these pools are among the rocks in one part

of a cave, while the ice is in another part.

I have said above that motion in subterranean ice is practically

wanting. This is proved by the lack of crevasses on the ice slopes

or ice walls, and also by the fact that basins and cones appear year

after year in the same spots, where they remain whether they are

increasing or diminishing. But this statement cannot be held to cover

the entrance snow and ice slopes of some of the open pit caves such as

the Gottscheer cave, or Saint-Livres or Haut d'Aviernoz. Here the snow,

which falls on the entrance slope, must gradually gravitate to the

bottom. The question is whether it only descends in the shape of water

after melting or as snow before solidifying; or whether it ever slides

down at all after becoming somewhat solidified. Probably, however, the

ice of these slopes, judging from the fact that crevasses are entirely

lacking, remains stationary.

_Color Effects._--The color effect of every glacière cavern has a

certain individuality, according to the color of the rocks, the

quantity of ice, and the amount of daylight admitted through the

entrance. In my opinion, the white note given by the ice, makes a fine

glacière cave the most beautiful of all subterranean hollows. In this

respect it seems to me that they are similar to high Alps, which are

certainly most impressive with coverings of snow and glacier.

There are, however, two distinct notes in the color effects of glacière

caves and these may be described as the partly subterranean, or as the

wholly subterranean. In the former case the local tints stand out more

clearly. For instance, at the Kolowratshöhle the ice is beautifully

transparent and of a pale ochre-greenish hue: the limestone rocks

are streaked with iron, and thus have a reddish hue, while, owing

to the entrance admitting plenty of daylight, the effect is only

semi-subterranean. Again, at Chaux-les-Passavant plenty of daylight is

admitted: the rocks are a yellowish brown, and the ice is white and

blue. At the Schafloch or the Frauenmauer, on the contrary, the effect

is wholly subterranean: daylight is so completely absent that black

is the predominating note, the ice itself looking gray. Dóbsina is an

exception, as, thanks to the electric light, white is the conspicuous

tone, even though rocks and shadows dull many places and corners into a

sombre gray.

More than once, on returning to daylight from the intense blackness

of a cave, I have seen the rocks near the entrance appear a dark

blue color, exactly simulating moonlight. This effect is common to

both glacière caves and ordinary caverns. It is a striking but rare

phenomenon, and depends apparently on the shape of the cave. This

moonlight effect only seems to occur when a cave makes an elbow

directly after the mouth and then goes straight for some distance. When

the daylight is actually in sight, the moonlight impression vanishes.

_Carbonic Acid Gas._--Carbonic acid gas, judging from the most

recent explorations, is more of a rarity in rock caves with normal

temperatures than is generally supposed. There appears to be only one

case on record where this gas was observed in a cold cave. This was

in the Creux-de-Souci,[33] which is rather a cold than a freezing

cavern, but which on one occasion was found to contain snow, and

whose temperature is always extremely low. From the present state of

knowledge, therefore, it may be assumed that if carbonic acid gas does

form in glacière caves, it does so only seldom.

[33] See Part III.: page 207.

_Fauna._--No attention whatever has been paid, practically as yet, as

to whether any distinctive animal life exists in glacières. So far, I

have seen none myself. The Rev. G. F. Browne, in four instances, found

a large red-brown fly nearly an inch long, which is supposed to be

_Stenophylax Hieroglyphicus_ of Stephens; and at Chapuis, he obtained

an ichneumon of the genus _Paniscus_. At Font d'Urle, Monsieur Villard

captured a blind specimen of a coleoptera, _Cytodromus dapsoïdes_.

A variety of rotifer, _Notholca longispina_, is now living in the

Creux-de-Souci. In Skerisora, remains of bats have been found, not very

different from those now living in the neighborhood.[34] It is, in any

case, certainly remarkable that the same kind of fly should have been

discovered in several glacières in different localities; and it may

some day be shown that there is a special insect fauna. Certainly the

subject is worth investigating.[35]

[34] See Part I.: Ausable Pond, page 81, and Part III.: Creux-de-Souci,

page 207; Font d'Urle, page 213; Chapuis, page 216; La Genollière, page

219; Skerisora, page 245.

[35] In June, 1899, I mentioned these facts to Monsieur Armand Viré,

director of the Biologic Laboratory in the catacombs of the Jardin

des Plantes in Paris. He was much interested, and promised to make a

careful investigation of the matter.

_Flora._--The flora of glacières has been as little observed as the

fauna. There are scarcely any references to such a thing as glacière

plant life in literature. Whether there is a special flora in any

glacière cave is still an open question. In the cases of several

boulder taluses, there is no doubt that, even if there is not a special

flora, at least that the plants near the ice beds are greatly retarded

every year in their development. Probably the flora among the boulders

blooms a month or six weeks later than the flora in the immediate

vicinity. In the cases of the Cave of Paradana and of the Kuntschner

Eishöhle it is reported that the plant life becomes more and more

arctic in character towards the bottom of the pit.[36]

[36] See Part I.: Ausable Pond, page 80; Giant of the Valley, page 83,

note 7; Ice Gulch, page 85; Spruce Creek, page 91. See Part III: Spruce

Creek, page 188; Paradana, page 237; Kuntschner Eishöhle, page 241.

_Paleontology._--No paleontological remains have as yet been reported

from glacière caves. No bones of animals have been found, except those

of bats in Skerisora[37] and a few of the common genus _bos_.[38]

No relics of the handiwork of man have been discovered; nor, indeed,

with the exception of the skeletons found in the cave of Yeermallik in

Kondooz,[39] anything which reveals the presence of man in glacières or

that they were ever used for habitation. The reason that there are so

few remains in glacière caves is undoubtedly because their temperatures

are too low for their occupation by animal or man; but, from the

evidence afforded by their non-occupation, may be drawn the valuable

inference that the glacière caves of to-day were glacière caves long

ago.

[37] See Part III.: Skerisora, page 245.

[38] See Part I.: Saint-Livres, page 68.

[39] See Part III.: Yeermallik, page 261.

_Legends and Religion._--There are scarcely any legends connected

with glacières. I know only of one about one of the caves of the Mont

Parmelan.[40] Nor does there seem to be any reference to glacière caves

in works of fiction. Dante makes his last hell full of an ice lake, but

an attentive perusal fails to reveal a single line which in any way

describes or suggests a glacière. In at least two cases,[41] however,

the ice in caves is connected with religion, as in Kashmere, the

Hindoos, and in Arizona, the Zuni Indians, either worship or pray at

glacière caves, overawed, from some mystical feeling, by the permanence

of the ice formations which they connect with their deities.

[40] See Part III.: Glacière de l'Enfer, page 216.

[41] See Part III.: Amarnath, page 262; Cave, White Mountains, Arizona,

page 176.

II.

The cause of the formation of subterranean ice is undoubtedly one

of the most intricate problems in connection with caverns. Various

theories have been advanced why ice is found in certain caves and not

in others. Some writers have held that it is a remnant of a glacial

period; others that it is owing to the presence of salts in the rocks;

some have said that it is due to the rocks retarding waves of heat

and cold; and still others think that it is formed by pressure on

the percolating waters. Many of these theories were formulated in

explanation of the belief of peasants living near the caves, who almost

always say that the ice is formed in summer and melts in winter. Most

scientific observers on the other hand claim that the ice is due to the

cold of winter, and a few think that it is formed or helped by draughts

and by evaporation and expansion of the air. The variety of opinions

put forth, show at any rate the intricacy of the problem.

All my own observations have tended more and more to make me believe

that the cold of winter is the cause of the ice. Before elaborating my

own views, however, I wish to take up seriatim the theories which have

been formulated, principally in explanation of the belief that the ice

was a summer product, and to give my reasons for my disbelief in them.

_Glacial Period._--The first theory, perhaps, to touch on, is the one

that the ice is a remnant of a glacial period. This seems to occur

to many persons as a solution of the question when they first hear

of glacières, and it has been several times propounded to me, and

naturally enough, always by scientific men.[42] Still I do not think it

has ever been held by anyone who had made a study of glacières.

[42] See Part IV.: Hitchcock, page 284; Bonney, page 291; Dawkins, page

292.

The theory is, indeed, untenable in regard to freezing caves, as it

does not accord with the observed facts of the yearly disappearance of

the ice in many caves and taluses. At Szilize every year the ice has

disappeared pretty completely by November, and the cave is free; but

in April or May the floor is again covered with ice, and columns and

icicles have formed on the roof and sides. At La Genollière the cave

is used by the people of the neighboring châlets, through the spring

and early summer, to help in the operation of butter making; by the

middle or the end of August it has entirely disappeared, but is found

formed afresh the following spring. At the Rumney Talus, at the Cave of

Decorah, at the Gorge of Ellenville, and at the Williamstown Snow Hole,

I found no snow or ice.[43] Yet it is abundant in all these localities

in the spring. Too many examples of the complete melting away of the

ice every year can be cited, to permit any doubt: glacière caves are

not connected with a glacial period.

[43] See Part I.: Rumney, page 85; Decorah, page 88; Ellenville, page

91; Williamstown, page 98.

Though it may be stated positively that the ice in caves is not a

remnant of a glacial period, yet this cannot be done so authoritatively

about subsoil ice sheets and freezing wells. At Brandon, Owego and

Decorah the gravel was found frozen at the time the wells were dug, and

it is of course impossible to determine for how long a time this was

the case previous to the digging. The proofs, however, are so strong

that the ice re-forms every winter at such freezing wells, that they

may be considered as in every respect following the same general laws

as glacière caves. That the ice in these wells is not the remains of a

glacial period, seems proved moreover by the work of the Boston Natural

History Society, which sank two wells at Brandon near to the Freezing

well. One of these was only twenty-one meters distant and went through

the same gravel drift. Yet it did not strike ice.[44] A somewhat

similar state of things appears to be the case with the Centennial Lode

and other lodes on Mount McClellan,[45] where the causes also seem to

be local, as there is no ice in mines on neighboring mountains.

[44] See Part IV.: Hager, page 282; Hitchcock, page 284.

[45] See Part III.: Rifts of Ice, etc., page 174.

_The Summer's Heat Theory._--The natives and peasants in the

neighborhood of glacière caves generally believe that the ice of

caves is formed in summer and melts in winter. I have met with this

belief everywhere in Europe; in the Eifel, Jura, Swiss Alps, Tyrolese

Alps, and Carpathians: and also occasionally in the United States.

Peasants and guides tell you with absolute confidence: "The hotter the

summer the more ice there is." The strange thing is that any number

of writers[46]--sometimes scientific men--have accepted the ideas and

statements of the peasants about the formation of ice in summer, and

have tried to account for it.

[46] Among them may be mentioned: Boisot, 1686; Valvasor, 1689;

Behrens, 1703; Billerez, 1712; Bel, 1739; Rosenmüller and Tillesius,

1799; Sartori, 1809; Pictet, 1822; Scrope, 1826; Murchison, 1845.

The belief of the peasants is founded on the fact that they scarcely

ever go to any cave except when some tourist takes them with him, and,

therefore, they rarely see one in winter, and their faith is not based

on observation. It is, however, founded on an appearance of truth:

and that is on the fact that the temperatures of glacière caves, like

that of other caves or that of cellars, are colder in summer than the

outside air, and warmer in winter than the outside air. Possessing

neither reasoning powers nor thermometers, the peasants simply go a

step further and say that glacière caves are cold in summer and hot in

winter.

Professor Thury tells a story to the point. He visited the Grand Cave

de Montarquis in mid-winter. All the peasants told him there would be

no use going, as there would be no ice in the cave. He tried to find

even one peasant who had been to the cave in winter, but could not. He

then visited it himself and found it full of hard ice. On his return

he told the peasants of his discovery. They were staggered at first,

finally one exclaimed: "It makes no difference; in genuine glacières

there is no ice in winter."

It will be difficult, probably, to eradicate this belief and the

consequent theories among the uneducated people in the vicinity of

glacière caves, for their imperfect observations will keep it alive. In

refutation, it may be said that the winter's cold theory is the direct

opposite of the summer's heat theory, and that all the observations and

all the facts which prove the one, disprove the other.

Within two or three years, however, the formation of small quantities

of ice has been observed during the summer months in one or two caves.

This has taken place in mountain caves situated at a high altitude at

times when the air outside has dropped below freezing point during the

night. There is, therefore, nothing inconsistent in this fact with the

winter's cold theory: indeed it is only a widening of it in the meaning

of the word winter.[47]

[47] See Part III.: Beilsteinhöhle, page 235. Part IV.: Professor

Cranmer, page 310.

_Chemical Causes._--Non-scientific persons, on first hearing of

glacière caves, almost always suggest that to form the ice there must

be salts in the rocks. Probably they connect unconsciously in their

minds "ice caves" and "ice cream."

Chemical causes, however, have never appealed to scientific men.[48]

There are only two places I know of where salt is reported. One is the

Ice Spring in Oregon, which is said to be slightly saline in taste; the

other is the Cave of Illetzkaya-Zatschita, where the gypsum hillock,

in which the ice is found, overlies a bed of rock salt. Repeated

experiments in letting lumps of glacière ice melt in my mouth have

convinced me personally that in all cases the water is exceedingly

pure and sweet, a fact mentioned in the very first notice extant about

glacières, the letter of Benigne Poissenot in 1586, who speaks of the

deliciousness of the water in Chaux-les-Passavant. To sum this matter

up briefly, it can be safely asserted that all causes, which would fall

under the head of "Chemical causes," must be entirely eliminated as

possible cold producers.

[48] See Part IV.: Billerez, page 270; Hacquet, page 271.

_Waves of Heat and Cold._--While Sir Roderick Murchison was studying

the geology of Russia,[49] he visited Illetzkaya-Zatschita and was

puzzled to account for the ice formations. He thought, at first, that

they were due to the presence of salt, but recognizing that this was

not correct he submitted the case to Sir John Herschel, who, rejecting

the evaporation or condensation of vapor as the cause, argued that

the ice was due to waves of heat and cold, and that at certain depths

in the interior, the cold wave arrived in mid-summer and the heat in

mid-winter. Murchison declined to assent to this doctrine, asking why

one cave should present this exceptional occurrence, when the numerous

other rents and openings in the same hillock were free from ice. The

impossibility of the heat and cold wave theory was so completely shown

by Murchison's objection, that it has never again been brought forward.

[49] _The Geology of Russia and the Ural Mountains_, vol. I., pages

184-198.

_Capillary or Compressed Air Theory._--The possibility of compressed

air causing subterranean ice to form seems to have been first

authoritatively formulated by Mr. N. M. Lowe, of Boston.[50] His theory

in brief is this:--Bubbles of air drawn into water flowing down through

fissures in rocks are liable to a continually increasing pressure. When

the air has reached the bottom and is liberated in the cave, it will be

from a pressure equal to the height of the column of water, and it will

have lost by connection in the mass through which the conduit passes,

the heat due to its compression; and on being liberated, it will

immediately absorb from the air and the water in the cave, the heat

which it has lost in its downward passage.

[50] _Science Observer._ Boston, 1879, vol. II., page 57. See Part IV.:

Silliman, page 279; Olmstead, page 282.

Several scientific observers have rallied to this idea.[51] One of

the Hungarian residents at Dóbsina, a doctor, whose opportunities

for observations are unrivalled, told me--if I understood him

correctly--that he believed in the capillary theory.

[51] See B. Schwalbe, _Ueber Eishöhlen und Eislöcher_, page 56.

There are many facts, however, which militate against the compressed

air theory as applied to caves. Almost all caves receive some drip

through fissures, and yet there are many thousands of caves which never

contain ice, and whose temperature scarcely varies the year round.

Especially against the theory is the fact that glacière caves are

never known in hot countries. If the theory were correct we should,

for instance, sometimes find ice in such caves as those of Yucatan

described by Mr. Mercer.[52]

[52] _The Hill Caves of Yucatan._

There are also some mechanical difficulties in the way. Mr. John

Ritchie[53] touches them when he says: "If the passage through which

the water flows down is at all tubular the column will be subjected to

the usual hydrostatic pressure." The word _tubular_ is the hard one to

answer. Limestone rock fissures are certainly not tubular. They have

all sorts of shapes and angles and corners, every one of which would

interfere with anything like a regular pressure.

[53] _Boston Transcript_, January 2d, 1897.

This latter objection would not apply to borings in mines. I have been

assured that in some borings in Western mines ice has been formed by

pressure, and there may be truth in this, although I doubt it, as

I have yet to hear of ice in any mines in warm latitudes. Mr. John

Ritchie[54] has suggested, also, that if compressed air does not

perhaps act strongly enough to form ice, yet it may help in keeping

the temperature low and aid in the formation of draughts in caves and

boulder heaps. At present, however, I can see no reason to think that

the ice in caves is due to compressed air.[55]

[54] _The Happy Thought._ Boston, January 23d, 1897.

[55] See Part I.: page 89.

III.

I have already said that I believe that the cold of winter is the

cause of the ice in caves. To make this clearer, I may say that I look

on glacières as the last outcrop, the outside edge, so to speak, of

the area of low temperatures, which has its culminating point in the

Northern Hemisphere in the Arctic Ocean, Greenland and Siberia, and in

the Southern Hemisphere in the Antarctic; and which is manifested to

us in the snows of mountain peaks, and immediately round us in frozen

ponds and rivers and snowy blizzards; and which, as it disappears each

summer, leaves its last traces in our latitudes in sequestered gorges

and convenient caverns. In every case, it seems to me, glacières are

simply refrigerators, which preserve the ice and snow accumulated in

them during the winter. They all follow the same general laws as to

the origin of their contents, modified only in slight degree according

to the varying natural local conditions, such as the water supply, or

the protection from sun and wind, or the thickness of the overhead

rock, or the altitude or latitude. I cannot see that there is anything

remarkable about the fact that the cold of winter is able to penetrate

and make itself felt sometimes for a slight depth in the earth's

crust; a depth, so far as yet known, never exceeding one hundred and

fifty meters. It seems to me that glacières only emphasize a law of

nature, which has doubtless been formulated many times in connection

with springs and phreatic waters, and that is, that where we find cold

waters underground, we may be sure that they have penetrated from the

outside.

If we look first at the mode of formation of overground perennial ice,

that is, of the ice of glaciers and of rock gorges; and then at the

evidences of the mode of formation of underground perennial ice, in

boulder heaps, wells and caves; we will soon see that the transitions

between them are gentle in character and that there is nothing

unnatural about the formation of the ice in glacières.

_Glaciers._--Everyone now knows the main characteristics of glaciers.

They are formed in parts of the earth where the land or the mountains

reach to the region of perpetual snow. The snows fall from the sky, and

accumulate into a snow cap, which by its own weight and by melting and

regelation, gradually changes to ice. This, by the laws of gravitation,

descends to lower levels, and in mountain valleys extends sometimes

far below the snow line into the region of cultivated fields. These

valley prolongations of the perpetual snow caps are the glaciers. The

important point to notice here, is that the formation of glaciers is

originally entirely due to the precipitation of moisture by cold in the

upper portions; while the destruction of glaciers is due to the action

of heat melting the ice in the lower portions, where they disappear in

the shape of streams of running water. It is, therefore, not surprising

that the greatest glaciers are found in the Arctic and Antarctic

regions and in the highest mountain ranges; and that in the tropics

glaciers are either wanting or exceedingly small.

_Gorges and Troughs._--Gorges and gullies, where ice remains over,

are a transitional form between glaciers and glacières. In many

mountain ravines or canyons, the enduring snow consists principally

of the avalanches which have fallen from the heights above during the

winter and solidified in the bottom of the ravines. Freezing gorges

proper, however, are not dependent on avalanches for their supply,

but they receive the accretions to their ice directly from the winter

snows. These fall into the gorge itself and by melting and regelation

gradually solidify into a mass of ice which, when well sheltered

against sun and wind, remains over sometimes till the following winter.

By their mode of formation, therefore, it is evident that the ice in

these gorges has some of the characteristics of glaciers; that it is

due to the same prime causes as the ice of glaciers or the ice on ponds

and rivers, namely the cold of winter; and in fact, it is not far

wrong to consider these gorges as miniature glaciers.

Freezing gorges, however, show, also, certain degrees of kinship to

freezing caverns and taluses, principally in the protection afforded

to the ice against external destructive influences. The ice is almost

always found in positions where it receives little, if any, of the

direct rays of the sun and, also, where it is scarcely, if at all,

exposed to any winds. The sides of the fissures and surrounding trees

generally afford the necessary protection. Some of the forms which the

ice assumes in gorges, such as long pendent icicles, are also more

characteristic of underground than of overground ice.

The freezing troughs or basins found in Siberia are evidently closely

related to gorges, and the fact that the ice is found in less sheltered

places may be explained by the high northerly latitudes of these

troughs, in general between fifty-seven and sixty degrees.

_The Winter's Cold Theory._--The places where ice is found underground

differ in one important respect from gullies and troughs, and that

is, in the fact that above the ice there is rock or soil, which, in

true caves, takes the form of a roof. This causes some important

distinctions between overground and underground perennial ice. It means

that the ice is formed directly in the caves, and that it is genuine

subterranean ice, and not, except perhaps near the entrance, solidified

snow. The roof, while not admitting the winter snows, is, however, a

protection against warm summer rains, and, of course, entirely cuts

off radiation from the sky. If, therefore, it keeps out some cold, it

also acts as a protector against heat.

That the cold of winter is the source of the cold which produces the

ice which forms underground, and that it is through its influence,

with the assistance of certain secondary causes, that some caves are

converted into what are practically natural ice houses, seems to me

the true explanation of the phenomenon of subterranean ice, not only

since it is the simple and obvious explanation, but also because all

the facts, so far as I have myself observed, are in accord with this

theory.[56]

[56] Among those who have written or said that the cold of winter plays

a more or less important part in the formation of subterranean ice

may be mentioned: Poissenot, 1586; Gollut, 1592; DeBoz, 1726; Nagel,

1747; Cossigny, 1750; Jars, 1774; Hacquet, 1778; Girod-Chantrans, 1783;

Hablizl, 1788; Prévost, 1789; Townson, 1797; Humboldt, 1814; Dearborn,

1822; Deluc, 1822; Dewey, 1822; Lee, 1824; Reich, 1834; Hayden, 1843;

Guyot, 1856; Rogers, 1856; Petruzzi, 1857; Smyth, 1858; Hager, 1861;

Thury, 1861; Browne, 1865; Raymond, 1869; Krenner, 1874; Ritchie,

1879; Benedict, 1881; Schwalbe, 1881; Fugger, 1883; Trouillet, 1885;

Girardot, 1886; Russell, 1890; Martel, 1892; Krauss, 1894; Lohmann,

1895; Balch, 1896; Cvijic, 1896; Butler, 1898; Kovarik, 1898; Cranmer,

1899.

To form subterranean ice, just as to form any other ice, two things are

necessary: the first is cold, the second is water. Cold is supplied by

the cold air of winter, and water must in some manner find its way into

the cave while the cold air is there.

The process is as follows: The cold air of winter sinks into and

permeates the cave, and in course of time freezes up all the water

which, in the shape of melting snow or cold winter rain or spring

water, finds its way in; and once ice is formed it remains long after

ice in the surrounding open country has melted away, because heat

penetrates with difficulty into the cave. The only effect of the heat

of summer is to melt the ice.

The proofs, to my mind, of the truth of this view are: 1--Glacières

are always found in parts of the world where, during part of the

year at least, the temperatures of the surrounding country fall

below freezing point. 2--All observations by reliable observers

show that the temperatures of glacière caves vary, but in a much

narrower thermometric scale, with those of the outside air: that the

temperatures are lowest, and as a rule below freezing point, during the

winter months; and that the temperatures are highest, and as a rule

above freezing point, during the summer months. 3--Ice is never found

far from the mouth of caves, but always near enough for the cold air

to get in. 4--Evaporation, according to my observations, is, as in all

other forms of ice in nature, connected mainly with the melting, not

the freezing of the ice.

_Geographical Distribution and Altitudes._--Glacière caves proper

are found in various parts of Europe, Asia, and America, mostly in

the smaller mountain ranges or in the outliers of the snowy mountain

chains; generally in limestone and occasionally in basaltic formations.

There are a good many in the Jura; a few in the Swiss and the Italian

Alps; a number in the Eastern Alps of Tyrol and Carinthia. There are

some in Hungary, several in Russia, one in Iceland, one on the Peak

of Teneriffe, a number in Siberia, one in Kondooz in Central Asia,

one in the Himálaya, one in Japan, and one in Korea. I have heard so

far of over fifty glacières in North America, several of which are in

Pennsylvania. From all over the world there are some three hundred

places reported where subterranean ice is said to occur. This includes

gorges, boulder heaps and freezing mines and wells, all of which exist

in much the same localities as glacière caves.

All the glacières which I know of, are situated in a latitude or at

an altitude where ice and snow forms for part of the year in the

surrounding open country. None are reported from India or Africa, or

in fact from any low-lying places in tropical latitudes. Most of them

are found in middle latitudes, and only where during part of the year,

at least, there is a cold season, that is, where for some time the

thermometer stands below freezing point.

Glacières are, in general, at fairly high altitudes. The Schafloch

is at 1780 meters; Skerisora in Transylvania at 1127 meters; Dóbsina

at 1100 meters; the Glacière de Saint-Georges at 1208 meters. It is

true that there is one freezing cavern in the sub-tropical latitude

of Teneriffe, La Cueva de la Nieve; but it is at an altitude of 3300

meters, and where snow falls every year in the open on the Peak.

Unless some freezing cave is hereafter discovered in a region where

there is no ice in the open in winter, I do not see how the imperative

necessity of the cold air of winter for forming the supply of ice can

be controverted.

_Thermometric Observations._--That the cold air of winter is the

important factor in the production of cold is proved, also, by the

thermometric observations recorded in various caves by different

observers. They all tell the same tale: that the temperatures vary with

those of the outside air, that they are lowest in winter and highest

in summer. I quote in the "List of Glacières"[57] a few of those

published; but there are many more, and they all show the same general

characteristics.

[57] See Part III.: Decorah, page 178; Chaux-les-Passavant, pages

203-5; La Poujade, page 208; Montarquis, page 218; Saint-Georges, page

219; Schafloch, page 223; Kolowratshöhle, page 227; Schellenberger

Eisgrotte, page 228; Frain, page 252; Dóbsina, page 253; etc.

A comparison of all the figures recorded proves that, as a rule--inside

of glacière caves--from about the first of November to the first

of July, there are winter temperatures, that is temperatures below

freezing point; and from about the first of July to the first of

November, there are summer temperatures, that is temperatures above

freezing point.

The observations prove also that the inner temperatures vary less than

the outer, that is that they range within narrower limits. They also

show that the inner air is but slowly affected by the outer air when

the latter is above freezing point, the inner temperature rising

then only gradually. Per contra, when the outside temperature drops

quickly much below freezing point, the inside temperature generally

drops correspondingly at once, proving that the cold air has sunk by

its weight into the cave. The observations also prove that the old idea

that the temperature of caves is the same throughout, can no longer

be considered correct. The observations also appear to show, that the

temperature of a cave does not necessarily represent the mean annual

temperature of a surrounding district. Observation is still entirely

lacking on the mean annual temperature of glacières, so that one cannot

speak definitely about the matter; but it seems likely that the mean

annual temperature of a glacière cave is lower than the isotherm of its

locality; and it seems more than probable that on the same isotherm

different glacière caves may have different mean annual temperatures,

varying with the elements of size, quantity of ice, position of body of

cave and of entrance, water supply and other factors.

_Ice near the Entrance of Caves and the Surface of the Soil._--An

important proof that it is the cold air of winter which forms the ice

is the fact that the latter is always found near the entrance of caves

or near the surface of the soil. It never extends far within. To the

best of my knowledge, ice has never been found two hundred meters from

the entrance nor at any depth beyond one hundred and fifty meters. In

all caves of great extent, the temperature far in is about the same as

that of the surrounding rock, and in all deep borings the temperature

increases with the depth and at great depths the temperature becomes

high. This nearness of subterranean ice to the outside air is one of

the best proofs, that, paradoxical as the whole phenomenon appears at

first, yet in reality it is an extremely simple matter.

The position of the entrance of a cave in relation to the body of the

cave is an important factor in permitting the cold air to permeate

and remain in the cave. In all the caves or gullies I have examined

myself, the main mass of ice is well below the level of the entrance,

and even if the latter is sheltered against the wind, it is not

sheltered against the cold air of winter. This is heavy, and by its own

weight sinks well down to the bottom, freezing up in course of time

all the moisture that may drip from the roof, or that may come into

the cave in the shape of melted snow or cold winter rain. The summer

air, which is warm and, therefore, light, can only enter the cave with

great difficulty; and, as a rule, before it dislodges the winter air

and destroys the ice, another winter's freeze reverses once more the

conditions. These principles seem to hold of every known glacière.

It is true, that at the Frauenmauer, the floor of the cavern rises

somewhat from the entrance; but the highest point of the floor is still

below the level of the top of the entrance, so that the cold air can

flow over the highest point without difficulty. The same appears to be

the case at the Posselthöhle; while at Amarnath in Kashmere, where the

floor is said to rise to the back wall, the entrance is about as large

as the area of the floor, so that the ice must also be below the level

of the top of the entrance.

The position or situation of the entrance is important. In almost all

cases it has a northerly exposure, and is sheltered against entering

winds. If these two conditions do not exist the ice supply surely

suffers. Sometimes the entrance is more or less tortuous. In some cases

it is protected by a fringe of trees. Still, there is no absolute rule

about entrances. The Friedrichsteinerhöhle faces about due south, and

at midday in summer, the sun shines all the way down to the ice floor,

causing mists to form. In the Kolowratshöhle, the entrance is badly

sheltered against the wind and this undoubtedly affects the supply in

summer and causes more rapid melting there than in some other cases.[58]

[58] See Part III.: Decorah, page 178.

Freezing boulder taluses invariably have the ice near the surface,

and probably it is never a dozen meters distant from the open air.

These taluses are one of the strongest links in the chain of evidence

proving the winter's cold theory. The snow and ice on the surface of

the taluses and on the surface of the boulders in gullies melts away,

while it still lingers underneath the boulders. It seems self-evident

that the melting snow water has run to the lowest level and there

congealed, and then remained because it was better sheltered than the

ice outside.

The subsoil ice of the tundras of Siberia and Alaska is almost

identical with the ice of boulder formations, except that it extends

under larger areas. It is the product of a climate where there is a

long, rigorous winter and it is not surprising that the ice is found at

greater depths than in more southerly latitudes.[59] The depth to which

the ice extends is, of course, determined by the depth to which the

winter's cold can penetrate the soil. There is no doubt that the causes

of this ice are local, that is, that it is due to the long prevailing

low temperatures.

[59] See Part III.: Alaska, page 166; Klondike, page 167; Kowak River,

page 166; Kotzebue Sound, page 166.

The freezing wells of which the most conspicuous examples are at

Brandon, Owego, Decorah, and in Montana, seem also due to local causes

and the ice is never far from the surface, that is, not over twenty

meters; and apparently also it forms above the water horizons which

supply the wells.

The ice sheet on Mount Etna[60] does not seem to be at any great depth.

It apparently had a different origin from most subterranean ice masses,

in that the snow probably fell first and was then covered by a flow of

lava. It is, therefore, almost _sui generis_ in its mode of formation,

unless there are similar sheets on other volcanoes, which is probable

in a country like Iceland, and which is said to be the case in Tierra

del Fuego,[61] But the original cause of the ice sheet on Etna was the

same as all other subterranean ice masses, namely the cold of winter.

[60] See Part III., page 210.

[61] See Part III., page 190.

_Evaporation and Movements of Air._--The formation of subterranean ice

is sometimes assigned partly to evaporation or to expansion of the air.

The theory is an old one, and both scientific and non-scientific men

have advanced it.[62]

[62] Among those who have written that evaporation is a factor in the

formation of subterranean ice, may be mentioned: Pictet, 1822; Scrope,

1827; Reich, 1834; Pleischl, 1841; Murchison, 1845; Olmstead, 1856;

Hitchcock, 1861; White, 1870; Kirchhoff, 1876; Krauss, 1895.

I have already said that I believe it is the movements of the air

which cause a cave to be a glacière cave or a normal cave. When they

act in such a way as to permit the cold air of winter to permeate a

cave, we find low temperatures and ice; when they do not, we find the

temperature about the same as that of the ground and no ice.

That the ice is not formed in apparently static caves, by movements

of air producing evaporation, seems to me proved by what I have

noticed in regard to the atmosphere. The dryness or moistness of the

air within a glacière cave is coincident with the state of freezing

or thawing of the cave. When I have visited a large cave in June,

everything was frozen tight, there were no drips nor mushy ice, the

air was relatively dry and the sensation of cold not unpleasant. When

I have visited a cave in August, the ice was soft and mushy, water

was dripping from the roof, the atmosphere was moist, and the cold

penetrating. It seems to me that the facts go to show that it is not

evaporation which forms the ice, but the melting of the ice which

fills the cave with moisture. If there are any draughts or movements

of the atmosphere when above freezing point, then their tendency is to

vaporize the ice.

The process of the formation of ice in relation to the atmosphere is as

follows: the cold air permeates the cave and freezes up all the drip:

the atmosphere becomes dry: gradually warmer air gets in and the ice

begins to melt: then the atmosphere gets charged slowly with the vapor

of the melting ice. This process is the exact opposite of the formation

of ice by evaporation; it is the atmosphere which is made humid by the

vaporizing of the ice, and by the drip. When the air is thoroughly

saturated with the vapor, being scarcely renewed from outside and but a

few degrees above freezing point, it undoubtedly retards evaporation,

acts like a blanket and lessens the rate of melting of the ice.[63]

[63] See Part IV.: Thury, page 285; Fugger, page 296; Trouillet, page

298.

Everything I have personally observed in freezing windholes shows

that in them also the cold of winter and not evaporation is the

cause of the ice. They answer to the same tests as other glacières,

of geographical distribution and altitude, nearness of ice to the

outside, thermometric observations, and dampness of the air when the

ice melts. Equally with other glacières, the movements of air in

windholes do not depend on the presence of ice, but the ice does depend

on the movements of air and a water supply at the proper time. A proof

that it is the cold of winter which makes the ice in windholes, is that

the ice is always found at the lower extremity, for the reason that it

is at that end that the cold air enters and to that end that the water

gravitates. The reason that ice is more rarely found in windholes than

in apparently static caves, is due to the movements of air. Unlike the

caves where the heavy cold air preserves the ice by remaining pent

up, as soon as the outside temperature rises the heavy cold air in

windholes tumbles out at the lower opening and is replaced gradually by

air at a higher temperature. This also flows out and when it is above

freezing point, it naturally melts the ice and becomes humid: in fact,

it vaporizes the ice as it passes, and dissipates the moisture into the

outer air.

It is, however, certain, that in caves with a temperature some degrees

above freezing point, when there is either running water or strong

drips, evaporation may be, and sometimes undoubtedly is, a factor in

lowering the temperature somewhat.[64] As in some windholes there

is occasionally moisture on the rock surfaces where the air current

passes, the evaporation from these surfaces doubtless lowers the

temperature of the draughts, and it may be, also those of the rock

surfaces, a little.

[64] See Part IV.: De Saussure, page 274. See also _Les Abimes_, 1894,

page 564.

Further observations, however, will be necessary in regard to

evaporation underground, as the data are still insufficient to make

absolutely positive statements.[65] I fail to see any evidence to show

that evaporation ever lowers the temperature of draughts underground

below freezing point, only that it may help to lower them to something

less than they would otherwise be. Taking all the facts which I have

myself observed, and all I have read of in the reports of others, my

own conclusion is that we have no proof that evaporation underground is

ever strong enough to produce ice.

[65] Several observers consider evaporation as more or less of a factor

in the production of cold underground. It is suggested also, that in

certain cases, at high altitudes, evaporation tends to prevent the

melting of the ice in windholes, but this is not proved, as yet. See

Part IV.: De Saussure, page 274; Fugger, page 296; Trouillet, page 298;

Martel, page 300; Lohmann, page 302.

_Time of Formation of Ice._--Everything I have seen points to the fact

that ice begins to form in a cave as soon as the temperature of the

cave has sunk below freezing point, whenever, from any cause, water

gets into the cave. The cold may begin to penetrate caves as soon

as outside frosts have occurred, that is in the fall months, about

November; and as soon as the temperature inside sinks below freezing

point, ice will begin to form, provided also that water gets into the

cave, from rains or springs or any other source.

In the mid-winter months, although there is then plenty of cold, the

water supply is generally lacking, as the outside moisture is mostly

frozen up and the result is that the winter months are not those

when the ice is mainly formed. Some is undoubtedly formed in certain

caves whenever during the course of the winter a surface thaw outside

furnishes water to the cave,[66] but in other cases this is not so and

the ice does not appear before the spring. In all cases it is in the

spring, before the cave has parted with its store of cold, and when

both the air and the rock walls are chilled below freezing point[67]

that the ice forms fastest. Then plenty of water is furnished by the

melting of the snows and the unlocking of the brooks, and also by early

spring rains. All this surface water runs through the fissures into

the still freezing cave and there becomes ice. Not only the air, but

also the rock walls are chilled below freezing point, and as the rocks

part slowly with the cold stored in them, this cold helps to freeze the

water pouring in.

[66] See Part III.: Chaux-les-Passavant, page 203; Saint-Georges, page

220.

[67] See Part IV.: Townson, page 275; Thury, page 285; Trouillet, page

297; Schwalbe, page 298; Terlanday, page 301; Kovarik, page 307.

The natural law in relation to time seems to be this: Ice may be formed

in caves as soon as the outside temperature sinks below freezing point.

In some caves it forms intermittently all through the cold months

because there is a water supply. In other caves it only forms in the

spring, because there is no water supply in the winter months. In all

cases, however, the end of winter is the time when most of the ice is

formed.

PART III.

LIST OF GLACIÈRES.

LIST OF GLACIÈRES.[68]

[68] This list is necessarily incomplete, and only approximately

accurate in many cases.

NORTH AMERICA.

Buried or Fossil Glaciers, North Greenland. (W. E. Meehan,

_Philadelphia Ledger_, 1896.)--On Robertson's Bay is the plateau of

the Verhoef Glacier, which is about 1500 meters long and 400 meters

wide, and stands back only a few meters from the edge of the sea. This

plateau, both top and sides, is a mass of flourishing vegetation,

chiefly grass, which reaches above a man's knee. From among this

verdure buttercups, poppies, cinquefoils and dandelions thrust their

golden heads in wild profusion. Similar buried glaciers are found in

many places along the fiords of North Greenland.

Mr. Meehan gives a simple explanation in connection with the Verhoef

Glacier. He says that this glacier formerly extended out into the sea,

and that while it moved forward, the clump moss, which struggles for

existence in Greenland gorges, could do little more than hold its own.

In course of time, from some unknown cause, the glacier receded to the

point where it now discharges, the part in the water floating away in

the shape of icebergs, and the part on the shore remaining stationary.

This was the opportunity for the clump mosses. Caring nothing for the

cold they crept slowly over the quiet mass of ice and made their way

first in thin net-like layers, later in thick masses, till they reached

the rocky shore. Year after year the mosses grew, the young plants

trampling underfoot the older; until the latter, rotting, turned into

a rich mould. The seeds of grasses and flowers found their way to

this, blown by the wind or carried on the feet of birds. The plateau

now is a garden of green, gold and white. How long this will last it

is impossible to say, as any time nature may unloose its hold, and the

frozen river once more pour down into the bay.

Subsoil Ice in Alaska. (I. C. Russell, _A Journey up the Yukon

River_, page 149, and _Second Expedition to Mount Saint Elias_, page

19.)--Professor Russell found ice covered by rocks and vegetation

in several places in Alaska, especially along the southern edge of

the Malaspina Glacier and on the Yukon River. He gives the following

interesting account in 1890 of these ice sheets: "Throughout the length

of the Yukon, one is frequently reminded of the high latitude drained

by the great river, by seeing strata of ice in the recently cut banks,

beneath the dense layer of moss and roots forming the surface on which

the forests grow. One may frequently find ice even on a hot summer's

day, by scraping away the moss at his feet. In some instances the

frozen layer has been penetrated to the depth of twenty-five feet, but

its full depth has never been ascertained. In the banks of some of the

streams to the north of the lower Yukon, strata of ice over a hundred

feet thick have been observed, and the indications are that its total

depth is considerably greater than the portion exposed. This subsoil

ice is stagnant and without the characteristics of glaciers."

Subsoil Ice in the Klondike Region. (_Philadelphia Ledger_, December

30th, 1897.)--The Klondike mining country is covered with snow most of

the year. The ground is frozen for ten or twelve meters in depth, down

to bed rock. In some places the ground, which is protected by a thick

moss, is not thawed out by the sun in summer. The miner cuts off the

moss with a shovel, and then builds a fire, which thaws out the ground

for five or ten centimeters. He digs this out, rebuilds a fire, and

then continues this process.

Ice Cliffs on the Kowak River, Alaska. (Lieutenant J. C. Cantwell,

_National Geographic Magazine_, October, 1896.)--On the shores of the

Kowak River are a series of ice cliffs of from about 25 meters to

45 meters in height. On top of these ice cliffs is a layer of black

silt-like soil some 2 meters in thickness, and from this springs a

luxuriant growth of mosses, grass and Arctic shrubbery. The melted ice

shows a residuum of fine dust, which while fresh emits a pungent odor.

Subterranean Ice Sheet on Kotzebue Sound. (Otto von Kotzebue,

_Entdeckungsreise in die Südsee_, etc. Weimar, 1821. Vol. IV., page

140.)--Dr. Eschholz discovered near Kotzebue Sound, in 1816, a mass of

ice more than 30 meters thick, and entirely covered with a layer at

least 15 centimeters thick of clay, sand, and earth, on which heavy,

long grass was growing. In the ice and in the soil overlaying it, were

many remains of extinct animals. On the side towards the ocean the ice

was entirely bare, exposed to sun and air, and much of it was melting

away in streamlets.

Freezing Lava Caves, Washington. (R. W. Raymond, _Overland Monthly_, 3d

November, 1869, page 421. Th. Kirchhoff, _Reisebilder und Skizzen aus

America_, 1876, vol. II., page 211. _Philadelphia Ledger_, September

25th, 1899.)--These caves are distant about four hours from the foot of

Mount Adams, and about 56 kilometers from the mouth of the White Salmon

River, where it falls into the Columbia River. The caves are in basalt,

and they are connected at both ends with the open air. Only a few of

them contain any ice, which in the largest cave is about 6 meters below

the entrance, from which one descends by a ladder. The cave opens on

one side and is some 15 meters in depth, 6 meters or 8 meters in width

and 3 meters or 4 meters in height. This part contains the most ice.

The other side gradually narrows from the entrance, is longer, and

reaches out through fallen rocks and rubbish to daylight. In the lower

portion, there are a few ice stalactites and stalagmites: one a superb,

transparent hillock, which rises nearly to the roof, is called the

Iceberg. A strong draught flows into the cave in summer through the

open arm.

The following paragraphs from the _Philadelphia Ledger_ probably refer

to the same locality:--

"Ice for the cutting, and that in August and early in September, is a

novelty not often found in regions as far south as the Columbia River

basin; but the novelty is enjoyed every year by people who visit the

ice caves under the shadow of Mount Adams, about 100 miles northeast

of Portland. It is a very extensive region. Frank McFarland, who has

just returned from a six weeks' vacation camping trip there, gives an

interesting account of its general make up.

"At the ice caves, which are six miles from Trout Lake, the stalactites

are more beautiful and wonderful this year than ever before, and this

was Mr. McFarland's fifteenth trip there. He broke off and took to camp

chunks of ice weighing 100 pounds. Pleasure parties who come to the

lake use considerable of the ice for packing their trout to take home.

All you have to do is to take a torch of pitch pine or a lantern, and

go into the big caves and pack off all the ice you want. It is a sure

crop, and never fails."

Ice Spring in the Rocky Mountains, Oregon. (G. Gibbs, _American Journal

of Science and Arts_, 1853, Second Series, vol. XV., page 146.)--The

Ice Spring is about 60 kilometers from the South Pass to the right of

the Sweetwater River. It is situated in a low marshy swale, where the

ground is filled with springs; and about 60 centimeters below the turf

is a sheet of horizontal ice, some 10 centimeters to 30 centimeters

thick, lasting throughout the year. The ice is clear and is disposed

in hexagonal prisms; it has a slightly saline taste, the ground above

it being impregnated with salt and the water near by tasting of sulphur.

Freezing Lava Caves in Modoc County, California. (_Dispatch_,

Frankford, Pennsylvania, 22d January, 1897, reprinted from another

paper.)--The lava beds, where the Modoc Indians made their last stand

against the United States troops, are described as an immense field of

lava covered with a beautiful forest of conifers. Numerous caves of

varying shapes and dimensions are scattered throughout these lava beds.

Some are mere covert ways, with an arch of stone thrown over them;

others are immense chambers some meters from the surface; another kind

sinks deeply and may be in a series of chambers united by a corridor

that opens at the surface; while another kind seems to go directly to

the centre of the earth without stopping. Some of these caves contain

ice and from them the Modocs drew their water supply while besieged by

the troops. Judging from what is reported of the caves the quantity of

ice in them must be large. The thermometer in winter in the region is

said to go as low as -30° C.

Freezing Lava Beds near Medicine Lake, Siskiyou County, Northern

California. (M. S. Baker, _Sierra Club Bulletin_, 1899. Vol. II., page

318.)--"One other feature of the lava region must be mentioned--the ice

caves. There are several of these known, and very likely many more

remain undiscovered. Those located along the edge of the lava, near the

cinder cone, I have known to contain ice and water as late as August.

The largest I have seen is on the Mayfield Road, about twenty miles

east of Bartles. It is situated in the barren lava, and in one of the

warmest localities of the region,--and there are few cool spots in the

lava anywhere. One enters the cave by crawling down a hole none too

large. The instant the interior is reached the temperature falls in a

surprising way. Not more than ten feet below the surface of the hot

rocks is a bed of ice, covered by a foot or so of ice water. The body

of ice was perhaps twelve or fifteen feet long, by five feet across

in the widest places. This cave is formed by a fissure that extends a

distance of twenty miles from the ice cave to Pittville, and nearly

coincides with the 4000 foot level, as shown in the map. Along the

southeastern half of this earth fissure the southwest wall has faulted,

leaving a cliff, which, in places, must be nearly 200 feet high."

Freezing Shafts, Montana.--Mr. Robert Butler, of San José, Cal., has

given me much information about glacières in Montana. He visited one

miners' shaft which is situated about 80 kilometers up the Rosebud

River from Rosebud Station on the Northern Pacific R. R., and about 10

kilometers northeast of the Cheyenne Indian Agency. It is on the north

slope of the Little Wolf Mountains, near the summit, at the head of

Greenleaf Creek. The canyon and surrounding slopes are covered with

a dense growth of pine. The rock has the appearance of scoriæ caused

by the burning of immense beds of coal in recent geological times. The

rock is broken into comparatively small pieces. The altitude is some

1200 meters. The forest, the volcanic ash and the altitude, besides

the loose rock formation, makes this place a natural ice house. Ten or

twelve years ago three prospectors, looking for silver, sunk a shaft

here. At a depth of about 4 meters it began to grow cold, and at 6

meters they found ice and imagined they could feel an upward draught.

Being ignorant and superstitious, they became frightened and abandoned

the shaft. During the winter, the snow fills the shaft half full of

ice, which then remains over through the summer. There is a general

report and belief among those who have visited the well, that it

freezes in summer and thaws in winter. There are thousands of mining

shafts in Montana, and if they are on the north slope of a mountain

of considerable altitude and under a dense forest and not too deep,

they generally have ice at the bottom during the summer. It is also

said to be nothing new for a miner in following crevices to find them

filled with ice, especially if near the surface on the north slope of a

mountain.

Freezing Cave, Fergus County, Montana.--Mr. Robert Butler, of San José,

Cal., visited this place, which is about 35 kilometers southeast of

Lewistown. It is on the north side of a butte. Masses of ice and great

icicles form in some parts of the cave in such quantities during the

latter part of winter that the cave furnishes ice for cooling the

drinking water for several dozen families. During July and August the

people come from some distance around to get the ice. The people in the

neighborhood believe that the ice forms in summer and thaws away in

winter. They also speak of the ever upward draught of cold air coming

possibly from some great hidden cavern in the lower recesses of the

mountain.

Freezing Well at Horse Plains, Montana. (Levi Allen, _Scientific

American_. New Series, 27th October, 1883.)--The well is described as

13.60 meters deep. It is dug through solid gravel, and in sinking it

there was encountered, at a depth of 10.60 meters, a current of air

strong enough to blow out a candle. It began to freeze in September,

1882, and in November it was frozen solid.

Freezing Silver Mine, Bighorn County, Wyoming.--This place is in the

Sunlight Basin of the Shoshone Mountains. Mr. William Worrell Wagner,

of Philadelphia, informs me that he visited it in August, 1897. It is

a silver mine or tunnel, running straight into the mountain for about

60 meters, at an altitude of about 3300 meters. The peaks of the Teton

range were in sight from the mouth of the tunnel. For the first half of

the way in, a good many icicles were hanging from the rocks. The last

half of the tunnel was thickly coated with ice and looked like a cold

storage plant. Snow disappears on the rocks outside about June, and

begins to fall again in September, so that Mr. Wagner's visit was at

about the hottest time of the year. Mr. Wagner presented the meat of a

bull wapiti he had shot to the miners, and they stored it in the mine

as if it had been an artificial refrigerator.

Rifts of Ice, Mount McClellan, Colorado. (Edward L. Berthoud, _American

Journal of Science and Arts_. Third Series, 1876, vol. XI., page

108.)--Near the summit of Mount McClellan, is the Centennial Lode,

which runs into the mountain, at an altitude of about 3900 meters.

Intercalated in the mineral vein are three or four well defined veins

of solid ice parallel with the bedding of the rock and filling all its

inner side-cracks and fissures. The same frozen substratum is found in

two other lodes near by on the same mountain. Nothing of the kind is

known on other Colorado mountains. The soil is loose and largely made

up of rocky débris, which shows that the ice is probably due to local

causes.

Freezing Tunnel on the Hagerman Pass, Colorado. (_Philadelphia Press_,

October 16th, 1897.)--The Hagerman Pass Railroad line is said to

have been abandoned after the completion of the Busk-Ivanhoe tunnel,

but to have been rebuilt. The Hagerman tunnel for a distance of over

700 meters was filled with solid ice, and it required blasting with

dynamite, and a month's continuous labor, day and night, to dig the ice

out.

Freezing Cavern in Cow Mountain, Colorado. (_Post Dispatch_, St. Louis,

Mo., July 13th, 1897, and September 5th, 1897. _Mail Order Monthly_,

St. Paul, Minn., October, 1899.)--The cave was discovered by parties

doing assessment work on a group of claims. A man was picking in a

three meter hole when he struck his pick into an opening, which was

gradually enlarged and showed a deep pit underneath. The men got a rope

and descended into an immense cavern full of ice. Later exploration

led to a small hall, some 5 meters in diameter, full of icicles. From

here a fissure led into a second rock chamber larger than the first. A

small hole in the floor at an angle of some 45° gave access to a third

and larger hall, about 25 meters by 40 meters. Great masses of ice were

found in this, also a small lake, about 12 meters by 20 meters. "Some

who have visited the wonderful discovery are of the opinion that it

is a great cave or fissure in a glacier which for centuries has been

slowly making its way down from Pike's Peak and whose waters are now

feeding the Arkansas River."

Windhole, Arizona. (_Christian Herald_, March 24th, 1897.)--Mr. Cofman,

while drilling a well on his place, is said to have opened a windhole

from which the escaping air current was strong enough to blow off the

hats of the men who were recovering the lost drill. Some days the air

escapes with such force that pebbles the size of peas are thrown up,

accompanied by a sound much like the distant bellowing of a fog horn.

Again for days there will be a suction current, unaccompanied by

sound, in which the current of air passes into the earth with somewhat

less force than when escaping, and any light object, as a feather or a

piece of paper, will be immediately sucked in. The account is probably

exaggerated.

Freezing Lava Cave near Flagstaff, Arizona.--Professor W. B. Scott of

Princeton University told me of this cave, which he had not visited

himself. It lies 14.5 kilometers south of Flagstaff, on the Mesa

table land, at an altitude of about 2000 meters. It was described to

Professor Scott as a double cave, with two floors, one over the other,

the lower containing the most ice. It is in lava, and can only be

entered by crawling in on hands and knees.

Freezing Cave or Gorge, White Mountains, Arizona.--Mr. Frank Hamilton

Cushing has told me of this place. It is a cleft among lava rock, which

being roofed at the further end, might be described as a cave. In this

the ice remains until June or July, much later than anywhere else in

the neighborhood. The Zuni Indians worship before this, calling the

ice the breath of the Gods, the snow they consider as a sort of down.

The region is arid, which makes any water precious, and this fact has

developed the element of mysticism about snow and ice among the Indians.

Freezing Cave near Galena, Black Hills, South Dakota. (Miss L. A.

Owen, _Cave Regions of the Ozarks and Black Hills_. Cincinnati, 1898,

page 209): "At Galena, a new mining town of golden promise, there is

reported to be an Ice Cave, where ice forms at all seasons, and during

the warm weather is a source of comfort and pleasure to the miners."

Windholes in the Ozark Mountains, Missouri.--Mr. H. F. Brinckerhoff,

of Aurora, Mo., informs me that there are a number of cold air current

caves in the Ozark Mountain region. One of them is some 19 kilometers

south of Aurora, Lawrence County, and is used for cold storage in

summer. There is a cave in a limestone bluff about 15 meters above a

river, and in the rear is this windhole, which is an opening about 30

centimeters high and 3 meters wide. A strong current of air comes out

from it in summer, and the hotter the air outside, the stronger is the

outward coming current. In winter the current is reversed. The outward

current is so strong in very hot weather that a handkerchief held in it

is straightened out to an angle of about 45°.

Freezing Cave and Well at Decorah, Iowa. Described in Part I. (Dr. C.

A. White, _Report of Geological Survey of State of Iowa_, 1870, vol.

I., page 80. A. F. Kovarik, _Scientific American Supplement_, No. 1195,

November 26th, 1898, pages 19,158, 19,159).

On June 1st, 1869, Dr. White found the ice dry and well frozen, and he

thought it was then accumulating. The cave was cool and apparently dry,

and no strong air current was passing through.

Mr. Alois F. Kovarik, of the Decorah Institute, has made a valuable

series of observations about the Decorah Cave. The temperatures he

observed were the following:

IN THE VALLEY, LOCUS

SHADE. DIVISION. GLACIALIS. END.

July 1, 1897 +33.3° +2.2° 0.0° 0.0°

" 27, " +21.1° +5.0° 0.0° 0.0°

Aug. 14, " +32.2° +5.8° +3.1° 0.0°

Sept. 3, " +32.2° +7.2° +3.1° +8.3°

" 18, " +33.9° +8.6° +6.1° +8.3°

Oct. 16, " +24.0° +10.0° +8.3° +8.3°

" 30, " +10.0° +7.2° +4.7° +5.0°

Dec. 11, " -2.2° -2.7° -1.1° -2.0°

Jan. 8, 1898 -0.0° -2.7° -3.9° 0.0°

" 22, " -5.0° -6.1° -3.9° -3.9°

Feb. 26, " -0.0° -6.6° -6.6° -5.0°

March 12, " +2.8° -1.6° -2.7° -2.7°

" 26, " +8.8° -1.7° -1.6° -1.1°

April 16, " +25.6° -1.4° +1.1° -1.1°

" 30, " +13.9° +1.1° -1.1° -1.1°

May 28, " +17.2° +1.7° -0.3° 0.0°

June 9, " +25.0° +1.7° -0.3° 0.0°

" 18, " +22.3° +1.7° -0.2° 0.0°

July 16, " +35.0° +7.2° 0.0° +2.2°

On the 1st of July, 1897, a cold breeze was noticed coming from the

cave to a distance of at least 30 meters. At the entrance the breeze

was strong enough to blow out a candle. This breeze was not noticed at

other times. From December to February inclusive, on the contrary, the

breeze was reversed. From July to October, 1897, the walls of the cave

were moist. From October to February they were dry. In February frost

began to appear on the walls. On March 12th, 1898, the walls were

covered with frost. The ice appeared at a spot nearly at the end of the

cave on the 26th of March, 1898. At a place about 6.50 meters nearer

the entrance, however, is where most ice forms. This place Mr. Kovarik

calls _Locus Glacialis_. The ice appeared here about the 29th of May,

1898. It increased rapidly up to June 12th, when it was at its maximum,

and was about two meters in width. It generally covers the north wall

from top to base. The greatest thickness in 1898 was 29 centimeters.

The temperature which Mr. Kovarik recorded on the 16th of April at

_Locus Glacialis_ of +1.1 seems an anomalous one. On writing to him

he sent me the following explanation: "April 16th, after I left the

thermometer at _Locus Glacialis_ the usual time, I noticed that it

registered +1.1° C. It seemed singular, for at both the Division and

the End, the thermometer registered considerably lower. I left the

thermometer at its place for about an hour longer, and noticed then

that it did not register differently. I would suggest this explanation:

This is true about water that upon freezing it gives off its latent

heat. Now on April 16th some water dripped into the cave on the wall

near where the thermometer was, about 1.50 meters from the floor. The

amount of water was very small, but as it came in contact with the cold

wall it began to give out its latent heat which affected the close by

thermometer. The temperature of the rock was without doubt between -1.°

and -3°."

Freezing Cavern at Brainard, Iowa. (Alois F. Kovarik, _Decorah Public

Opinion_, September 20th, 1899.)--This little cave is situated on the

north side of a hill about 1.5 kilometers northwest of Brainard. It is

about 4.50 meters deep. On June 10th, 1899, Mr. Kovarik found the floor

and walls covered with ice. The temperature was 0° C. The owner claims

to have taken enough ice out of it on July 4th, 1897, to freeze cream.