Northern Lakes of America._--At a meeting of the American Academy,
February 1849, Mr Foster, of the United States Mineral Survey in the
North-west Territory, presented the result of some observations,
undertaken with a view of determining whether the waters of the
northern lakes are subject to any movements corresponding to tidal
action. The result of these observations had convinced him that these
waters do not rise and fall at stated periods, corresponding to the
ebb and flow of the tide, but are subject to extraordinary risings,
which are independent of the influence of the sun and moon. These
risings attracted the attention of the earliest _voyageurs_ in these
regions. Charlevoix, who traversed the lakes nearly a century ago,
says, in reference to Lake Ontario:--"I observed that in this lake
there is a sort of reflux and flux almost instantaneous; the rocks
near the banks being covered with water, and uncovered again several
times in the space of a quarter of an hour, even if the surface of the
lake was very calm, with scarce a breath of air. After reflecting some
time on this appearance, _I imagined it was owing to springs at the
bottom of the lake, and to the shock of their currents with those of
the rivers which fall into them from all sides, and thus produce those
intermitting motions_." The same movements were noticed by Mackenzie
in 1789; by an expedition under Colonel Bradstreet in 1764; on Lake
Erie in 1823, and at various later periods. In the summer of 1834, an
extraordinary retrocession of the waters of Lake Superior took place
at the outlet of Sault St Marie. The river at this place is nearly a
mile wide, and in the distance of a mile falls 18·5 feet. The
phenomena occurred about noon. The day was calm, but cloudy. The water
retired suddenly, leaving the bed of the river bare, except for a
distance of thirty rods, and remained so for nearly an hour. Persons
went out and caught fish in pools formed in the depressions of the
rocks. The return of the waters is represented as having been very
grand. They came down like an immense surge, and so sudden was it,
that those engaged in catching fish had barely time to escape being
overwhelmed. In the summer of 1847, on one occasion the water rose and
fell at intervals of about fifteen minutes during an entire afternoon.
The variation was from twelve to twenty inches, the day being calm and
clear; but the barometer was falling. Before the expiration of
forty-eight hours, a violent gale set in. At Copper harbour, the ebb
and flow of the water through narrow inlets and estuaries has been
repeatedly noticed when there was not a breath of wind on the lake.
Similar phenomena occur on several of the Swiss lakes. Professor
Mather, who observed the barometer at Copper harbour during one of
these fluctuations, remarks:--"As a general thing, fluctuations in the
barometer accompanied fluctuations in the level of the water; but
sometimes the water-level varied rapidly in the harbour, while no such
variations occurred in the barometer at the place of observation."
As a general rule, these variations in the water-level indicate the
approach of a storm, or a disturbed state of the atmosphere. The
barometer is not sufficiently sensitive to indicate the sudden
elevations and depressions, recurring, as they often do, at intervals
of ten or twelve minutes; and the result of observations at such time
may, in some degree, be regarded as negative. Besides, it may not
unfrequently happen, that, while effects are witnessed at the place of
observation, the cause which produced them may be so far removed as
not to influence the barometer. We are, therefore, led to infer that
these phenomena result, not from the prevalence of the winds acting on
the water, accumulating it at one point and depressing it at others,
but from sudden and local changes in the pressure of the atmosphere,
giving rise to a series of barometric waves. The water, conforming to
the laws which govern two fluids thus relatively situated, would
accumulate where the pressure was the least, and be displaced where it
was the greatest. It has been remarked by De la Beche, that a sudden
impulse given to the particles of water, either by a suddenly
increased or diminished pressure, would cause a perpendicular rise or
fall, in the manner of a wave, beyond the height or depth strictly due
to the mere weight itself. The difference in the specific gravity of
the water of the lakes and the ocean may cause these changes to be
more marked in the former than in the latter.--_American Annual of
Scientific Discovery_, p. 245.
4. _Water Thermometer._--Lieut. Maury states that he has been very
much assisted in developing his theory of winds and currents by means
of the thermometer used by some vessels for determining the
temperature of the water. It was by means of these observations on the
temperature of the water that he was enabled to prove that, off the
shores of South America, between the parallels of 35° and 40° south,
there is a region of the ocean in which the temperature is as high as
that of our own Gulf stream, while in the middle of the ocean, and
between the same parallels, the temperature of the water is not so
great by 22°. Now, this very region is noted for its gales, being the
most stormy that the as yet incomplete charts of the South Atlantic
indicate. Lieut. Maury says, however, that very few navigators make
use of the water thermometer, so that he has experienced some
inconvenience in his undertaking. He is the more surprised at this,
from the fact that New York owes much of her commercial importance to
a discovery that was made by this thermometer. At the time when Dr
Franklin discovered the Gulf Stream, Charleston had more foreign trade
than New York and all the New England States together. Charleston was
then the half-way house between New and Old England. When a vessel, in
attempting to enter the Delaware or Sandy Hook, met a north-west gale
or snow storm, as at certain seasons she is apt to do, instead of
running off for a few hours into the Gulf Stream to thaw and get warm,
as she now does, she used to put off for Charleston or the West
Indies, and there remained till the return of spring before making
another attempt. A beautiful instance this of the importance and
bearings of a single fact, elicited by science from the works of
nature.--_Annual of Scientific Discovery_, p. 160.
5. _On the Falls of Niagara._--If we follow the chasm cut by the
Niagara river, down to Lake Ontario, we have a succession of strata
coming to the surface of various character and formation. These strata
dip south-west or towards the Falls, so that, in their progress to
their present position, the Falls have had a bed of very various
consistency. Some of these strata, as the shales and medina sandstone,
are very soft, and, when they formed the edge of the Fall, it probably
had the character of rapids; but, wherever it comes to an edge of hard
rock, with softer rock-beds below, the softer beds, crumbling away,
leave a shelf projecting above, and then the fall is perpendicular.
Such is the case at present; the hard Niagara limestone overhangs in
_tables_ the soft shales underneath, which at last are worn away to
such an extent as to undermine the superincumbent rocks. Such was also
the case at Queenston, where the Clinton group formed the edge, with
the medina sandstone below. This process has continued from the time
when the Niagara fell directly into Lake Ontario to the present time,
and will continue so long as there are soft beds underneath hard ones;
but, from the inclination of the strata, this will not always be the
case. A time will come when the rock below will also be hard. Then,
probably, the Falls will be nearly stationary, and may lose much of
their beauty from the wearing away of the edge rendering it an
inclined plane. I do not think the waters of Lake Erie will ever fall
into Lake Ontario without any intermediate cascade. The Niagara shales
are so extensive that possibly, at some future time, the river below
the cascade may be enlarged into a lake, and thus the force of the
falling water diminished; but the whole process is so slow, that no
accurate calculations can be made. The Falls were probably larger, and
stationary for a longer time at the "Whirlpool" than anywhere else. At
that point there was no division of the cataract, but at the "Devil's
Hole" there are indications of a lateral fall, probably similar to
what is now called the American Fall. At the Whirlpool, the rocks are
still united beneath the water, shewing that they were once continuous
above its surface also.[89]--_Agassiz on Lake Superior_, p. 15.
Footnote 89: The data on which these and the previous remarks on
the geology of the Falls are founded, are derived from Professor
James Hall's investigations in the New York State Survey. A.
6. _On the Existence of Manganese in Water._--At a meeting of the
American Academy, in January 1849, Dr Charles T. Jackson stated that
he had discovered the presence of manganese in the water of streams,
lakes, &c., almost universally. He detected it in water from the
middle of Lake Superior, in Cochituate water, and in water from
various sources. It has usually been regarded as iron in previous
analyses. He considered the observation as having an important bearing
in accounting for the deposits of bog manganese at the outlets of
ponds, lakes, and in bogs, as well as for the source of the oxide of
manganese in the blood.--_Annual of Scientific Discovery_, p. 202.
_On the Presence of Organic Matter in Water._--The following facts
relative to the presence of organic matter in water were presented to
the British Association, by Professor Forchhammer, as the result of
extended observations on the water, near Copenhagen.
_1st_, The quantity of organic matter in water is greatest in summer.
_2d_, It disappears, for the most part, as soon as the water freezes.
_3d_, Its quantity is diminished by rain. _4th_, Its quantity is
diminished if the water has to run a long way in open channels. The
hypermanganate of potash or soda is recommended by the Professor as a
most excellent test for the presence of organic matter in water.
7. _Arsenic in Chalybeate Springs._--Since the discovery of arsenic in
the deposits from certain chalybeate springs, it has been asked
whether the poisonous properties of this substance are not neutralized
by the state in which it is found. M. Lassaigne has finished a series
of experiments connected with this subject, for the purpose of
ascertaining the proportion of arsenic contained, in what state of
combination it exists, and the nature of the action which these
arseniferous deposits exert in the animal economy. The following are
M. Lassaigne's conclusions:--1. In the natural deposits of the mineral
waters of Wattviller, arsenic exists to the amount of 2·8 per cent. 2.
A portion of these deposits, representing 1·76 grains of arsenic acid,
or 1·14 grains of arsenic, produced no effect upon the health of a
dog. 3. This non-action shews that the poisonous property of the
arsenic is destroyed by its combination with the peroxide of iron, and
thus confirms what has been before asserted, that peroxide of iron, by
combining with arsenious and arsenic acid, destroys their poisonous
properties, and consequently becomes an antidote for them.
GEOLOGY.
8. _The Coal Formation of America._--The coal regions of America are,
from the explorations which have thus far been made, supposed to be
divided into three principal masses; the great central tract,
extending from Tuscaloosa, Alabama, to the west of Pennsylvania, and
being apparently continued to New Brunswick and Nova Scotia; the
second tract strikes north-westward from Kentucky, crosses the Ohio,
and stretches through Illinois to the Mississippi River; a third
region, smaller than the others, lies between the three great
lakes--Erie, Huron, and Michigan. Competent geologists affirm that,
from a comparison of the coal strata of contiguous basins, these are
no more than detached parts of a once continuous deposit.
The extent of this enormous coal field is, in length, from north-east
to south-west, more than 720 miles, and its greatest breadth about 180
miles; its area, upon a moderate calculation, amounts to 63,000 square
miles! In addition to these, there are several detached tracts of
anthracite in Eastern Pennsylvania, which form some of the most
remarkable coal tracts in the world. They occupy an area of about 200
square miles.
The strata which constitute this vast deposit comprehend nearly all
the known varieties of coal, from the dryest and most compact
anthracite to the most fusible and combustible common coal. One of the
most remarkable features of these coal-seams is their prodigious bulk.
The great bed of Pittsburgh, extending nearly the entire length of the
Monongahela River, has been traced through a great elliptic area, of
nearly 225 miles in its longest diameter, and of the maximum breadth
of about 100 miles, the superficial extent being 14,000 square miles,
the thickness of the bed diminishing gradually from 12 or 14 feet to 2
feet. In 1847 the anthracite coal regions of Pennsylvania furnished
3,000,000 tons, and 11,439 vessels cleared from Philadelphia in that
year, loaded with the article. The produce in 1848 and the present
year, is of course larger.
The bituminous coal area of the United States is 133,132 square miles,
or one 17th part of the whole. The bituminous coal area of British
America is 18,000 square miles, or one 45th part; Great Britain, 8139
square miles; Spain, 3408 square miles, or one 52d part; France, 1719
square miles, or one 118th part; and Belgium, 518 square miles, or one
122d part. The area of the Pennsylvania anthracite coal formations is
put down at 437 square miles; and that of Great Britain and Ireland
anthracite and culm, at 3720 square miles. The anthracite coal of
Great Britain and Ireland, however, is not nearly so valuable an
article of fuel as the anthracite coal of Pennsylvania, nor does a
given area yield so much as the latter.--_New York Express._ _American
Annual of Scientific Discovery_, p. 271.
9. _River Terraces of the Connecticut Valley._--At the meeting of the
American Association in August, President Hitchcock of Amherst
College, read a paper "On the River Terraces of the Connecticut
Valley, and on the Erosions of the Earth's Surface." He stated that
his paper must be considered as containing a few facts and suggestions
and not a finished theory. He has examined the valley from its mouth
to Turner's Falls, and carefully measured the heights of the terraces.
"As you approach the river you find plains of sand, gravel, or loam,
terminated by a slope sometimes as steep as 35°, and a second plain,
then another slope and another plain, and so on, sometimes to a great
number. I find that these terraces occur in successive basins, formed
by the approaches of the mountains upon the banks at intervals.
Sometimes the basin will be 15 or 20 miles in width, but usually much
narrower; and it is upon the margins of these basins that the terraces
are formed. I have rarely found terraces more than 200 feet above the
river, which would be in Massachusetts, about 300 feet above the
ocean, and at Hanover, N.H., about 560 feet. Nowhere do they exist
along any river, unless that river has basins. As to the materials of
which they are formed they appear exceedingly artificial. The outer or
highest terrace is generally composed of coarser materials than the
inner ones. They are all composed of materials which are worn from the
rocks, but the outer terrace oftener is full of pebbles, some of them
as large as 12 inches, while the materials of the inner seem reduced
to an impalpable powder, like the soil of a meadow which is overflowed
during high water. Whence did these materials originate? The materials
were first worn from solid rocks, and afterwards brought into these
valleys. The outer terrace appears to have been often in part the
result of the drift agency. Afterwards, the river agency sorted the
materials, and gave them a level surface, the successive basins having
at that time barriers. The inner terrace appears to have been, at
least in its upper part, the result of deposition from the river
itself.
"I will now mention a few facts which I have observed. The terraces do
not generally agree in height upon the opposite sides of the valley.
The higher ones oftener agree, perhaps, than the lower ones. If
formed, as I suppose, from the rivers, we should expect this. The
terraces slope downwards in the direction of the stream. The same
terrace which, near South Hadley, is 190 feet above the river, slopes
until, at East Hartford, it is only 40 feet above the river, thus
sloping 150 feet more than the slope of the river itself, in a
distance of 40 or 50 miles. This shows that they could not have been
formed by the sea or by a lake, for they would then have been
horizontal. The greatest number of terraces observed is eight or nine.
Generally there are but two or three." President Hitchcock then gives
his view of the precise mode in which these terraces were formed,
illustrating them by references to other parts of our country, and
concludes by a notice of the erosions of the earth's surface.--_Annual
of Scientific Discovery_, 1850, p. 229.
ZOOLOGY.
10. _Fossil Crinoids of the United States._--At the meeting of the
American Association, 1849, a paper on the fossil crinoids of
Tennessee, by Professor Troost, was read by Professor Agassiz.[90] The
species embraced are not less than eighty-eight in number, of which
only half a dozen have been described. It is the opinion of Professor
Hall that all the silurian formations of New York, previous to the
beginning of the geological survey, did not afford more than four or
five. Now, about sixty species have been ascertained. Professor Hall
mentioned the fact, that all the crinoids of the lower silurian rocks,
with the exception of one species, have five pelvic plates, and we
never find one with three, or any other number of these plates, before
we reach the highest deposits. In Tennessee, the crinoids are so
abundant, that Professor Troost states that he had been able to
collect some 300 or 400 good specimens of seven or eight different
species in a single morning. In relation to the abundance of these
fossils in the United States, Professor Agassiz remarked, that it is
not, perhaps, sufficiently appreciated of what importance, and of what
immense value the study of these fossil crinoids may be for the
progress of palæontology. American students should be proud of these
materials, by which they will be able to throw so much light upon
these almost extinct families by their personal investigations, which
will not only render them independent of the palæontologist from
abroad for information with regard to the succession of types, and the
full illustration of these structures, but really afford correct
standards for comparison. It is the more desirable that all these
fossils should be made known, as the family of crinoids is so reduced
in our days that we can form no idea of the living animals of that
group, of their diversity of form, modification of character, and
peculiarity of position, from the living type only. He doubted whether
the number of crinoid heads of all species found in Europe, now
existing in the Museums of Europe, is one-third the number of those
which have been found by a single gentleman in Tennessee in one
morning. Now, with such materials, consider what precise and what
minute investigations could be made. And if these facts could be once
fully ascertained and well illustrated, there is no doubt that the
series of crinoids, and their succession in former ages, will be
established from American standards, and will no longer rest upon the
European evidence, which has often been derived from the examination
of small fragments of those ancient fossils, found in unconnected
basins for the most part, so that their geological succession could be
ascertained only with great doubt and difficulty. In conclusion,
Professor Agassiz would venture to say, that geologists who have had
any opportunity to compare the position of the ancient rocks on this
continent of North America with the corresponding deposits of Europe,
would agree with him in saying that the geology proper, the
stratography of North America, will afford the same precise and well
authenticated standards for the appreciation of the order of
succession of rocks, as fossils will for the order of succession of
living beings.--_American Annual of Scientific Discovery_, p. 282.
Footnote 90: These fossiliferous remains were discovered in the
carbonaceous and silurian strata of the State, and shew a
wonderful development of that form of animal on the shores during
the palæozoic period. Thirty-one genera, sixteen of which are
considered by Professor Troost as new, are enumerated.
11. _Discovery of Coral Animals on the Coast of
Massachusetts._--Professor Agassiz, while on an expedition in one of
the vessels of the coast survey during the past summer, obtained by
means of a dredge, from a depth of seventy-two feet, in the Vineyard
Sound off Gay Head, several specimens of a coral with its animals. By
great care and attention they were preserved alive in glass jars for
more than six weeks, and afforded an excellent opportunity for an
examination and observation of their structure and habits. These
corals belong to the genus _Astrangia_, and have been named by
Professor Agassiz, in honour of Professor Dana, geologist of the
exploring expedition, Astrangia Dana.
This species presents two varieties. Some are of a pink or rose
colour, others are white. The general form of the animal is a cylinder
(as of all Polypi) resting on its base, and expanded on the upper
margin; thus expanded it is about two lines in diameter. The number of
tentacles is definite, but it is not always the same absolute number.
It never exceeds twenty-four; in earlier periods of life there are
only twelve, and there is even an epoch when there are only six.
It is, perhaps, a matter of surprise that the coral animal should have
been found in this latitude. They teem in the warm latitudes; but
there are very few species in the more temperate regions, and but for
the opportunity afforded by the coast survey, the existence of these
animals could not have been suspected on these shores. For many years,
however, dead fragments had been found along the shores; but whether
they lived there naturally or not had not been ascertained.--_American
Annual of Scientific Discovery_, p. 311.
12. _On the Circulation and Digestion of the Lower
Animals._--Professor Agassiz states, that the circulation of the
invertebrata cannot be compared to that of the vertebrata. Instead of
the three conditions of chyme, chyle, and blood, which the circulating
fluid of the vertebrata undergoes, the blood of that class of the
invertebrata which he had particularly studied, the annelida or worms,
is simple coloured chyle. The receptacles of chyle in different parts
of the body are true lymphatic hearts, like those found in the
vertebrata; this kind of circulation is found in the articulata and
mollusks, with few exceptions, and in some of the echinoderms. In the
medusæ and polyps, instead of chyle, chyme mixed with water is
circulated; this circulation is found in some mollusks and intestinal
worms. Professor Agassiz thinks, that the embryological development of
the higher animals shews a similar succession in the circulating
function. As regards the connection between respiration and
circulation in vertebrata, the gills are found between branches of the
blood system; in invertebrata, the chyliferous system is acted on by
the respiration. The gills of fishes, therefore, cannot be compared to
the gills of crustacea, articulata, and mollusks. In fact, no gills
are connected with the chymiferous circulation. Animals having this
circulation, have no true respiration. They have only tubes to
distribute freshly aërated water to different parts of the
body.--_Proc. Bost. Nat. Hist. Soc._