From this tabulating of them it is apparent that the doubles are

practically confined to the zones within forty degrees of the equator.

Only 7% of them straggle farther north than this, while above 63° north

latitude and 35° south latitude there are none. Such a distribution is

not in proportion to the areas of the zones, which though diminishing

toward the poles do so at no such rate. The surface included between

the equator and 40° of latitude is 65% of the hemisphere, whereas the

fraction of the number of doubles found there is 93%. The doubles are,

then, an equatorial feature of the planet, confined to the tropic and

temperate belts.

To perceive the tropical character of the doubles in another way we

have but to consider the zonal distribution of the single canals.

Unlike the former the latter do not thin out as one advances toward the

poles; since in the arctic regions single canals bemesh the surface as

meticulously as elsewhere. It is only that they there replace the

doubles; or, not to put the cart before the horse, it is the doubles

that in part replace the singles in the tropics. And that this

arrangement has something physical behind it by way of cause is

curiously shown by two canals, the Arnon and the Kison, which are

neither of the one kind nor yet the other, but a cross between the two.

For the Arnon and the Kison are convergent doubles; the two lines of

the Kison leaving a common point at the edge of the polar cap and

separating as they travel south, while the two Arnon take up and

continue the divergence, connecting at last with the parallel pair of

the Euphrates. These canals thus make transition between the true

doubles and the true singles, and may be looked upon as endowed with

the potentialities of both. From their association with the double

Euphrates, it is clear that the transition between the two forms is not

only formal but physical, and that the stopping of the dual condition

at the fortieth parallel is not the outcome of chance.

It may occur to the thoughtful that the doubles appear confined to the

more tropical portions of the planet because of a better presentation

of those zones, the reader supposing the planet to be seen axised

perpendicularly to the plane of sight, as geographies represent the

earth’s globe. The supposition, however, is erroneous. We sometimes see

the planet so, but more often not. Such is the tilt of the Martian axis

to the plane of the Martian ecliptic that the different zones are

rarely seen on an even keel, so to speak, their aspects shifting

totally from one opposition to another. What shows in mid-disk on one

occasion may be forty-eight degrees removed from it at another, a

distance amounting to three-quarters of the way from apparent equator

to apparent pole.

Thus the double canals are for some intrinsic reason equatorial

features of the planet as opposed to polar ones. And this not simply

because of greater space there. Duality is a result of conditions

intrinsic to the several localities. What the cause may be is related

to the character of the things themselves, which we shall later

consider. For the moment we may note that the fact disposes quietly of

the diplopic theory of their manufacture. For, for diplopic doubles to

show such respect for the equator would betoken a courtesy in them to

be commended of Sydney Smith.

But this is not their only geographic bias. In addition to not being

partial to the poles, the double canals show a certain exclusiveness

toward the dark areas generally. Not only do they avoid the arctic and

antarctic zones entirely, but they largely shun the blue-green regions.

In these but two suspicions of doubles occur, in the Aonium Sinus,

although single canals there are as numerous as anywhere else on the

planet.

Nevertheless, although they avoid running through them, they run from

them in a manner that is marked. Proceeding from the great diaphragm

are no less than 28 out of the 53 doubles. Connecting directly with

these are 17 more; while the remaining 8 are also associated through

the intermediarism of dark areas, the Solis Lacus and the Trivium.

In like relation to dark regions, they are limited on the north by the

Mare Acidalium, the Propontis, the Wedge of Casius and their

interconnecting bands, the Pierius, Callirrhoe, Helicon. In this manner

do they form a broad girdle round the planet’s waist, leaving the polar

extremities bare.

-----

Footnote 4:

Very wide and possibly not of the same class.

CHAPTER XIX

CANALS IN THE DARK REGIONS

Seventeen years after the recognition of the canals in the light

regions occurred another important event, the discovery of a similar

set in the dark ones. The detection of these markings in the dark areas

was a more difficult feat than the perceiving of those in the light,

and in consequence was later accomplished. Also was it one where

recognition came by degrees.

I have previously pointed out what this discovery did for the

seas—nothing less than the taking away of their character in a

generally convincing manner. To one who had carefully considered the

matter, the seas had indeed already lost it, as was shown in Chapter X,

but to those who had not these canals presented a very instant proof of

the fact.

From such not wholly supererogatory service they went on to furnish

unlooked-for help in other directions. Their discovery showed in the

first place that no part of the planet’s surface was free from canal

triangulation.

But it did more than this. For these canals in the dark regions left

the edge of the ‘continents’ at the very points where the canals of the

light regions entered them, which fact proved for them a community of

interest with the latter. Such continuation was highly significant,

since it linked the two together into a single system, compassing the

whole surface of the planet. Starting from the places where the

light-region canals come out upon the great girdle of seas that

stretches all round the planet, most of the new canals headed toward

the passes between the islands south, as nearly polewards as

circumstances of local topography would permit. In the broader expanses

of the Syrtis Major and the Mare Erythraeum, besides main arteries

others went to spots in their midst after the same fashion as those of

the light regions. These spots differed in no way apparently from their

fellow oases elsewhere. From a spot in the centre of the Syrtis three

great lines thus traveled south: the Dosaron, heading straight up the

Syrtis on the meridian till it struck the northernmost point of Hellas;

the Orosines, inclined more to the right, passing through the dark

channel to the west of that land and so proceeding south; and lastly

the Erymanthus turning eastward till it brought up finally at the

Hesperidum Lucus. Where, on the other hand, the long chain of lighter

land, called by Schiaparelli islands, and stretching from the Solis

Lacus region westward to Hellas, offered only here and there an exit,

the canals made for these exits. The canals in the Mare Sirenum, the

Mare Cimmerium, and the Mare Tyrrhenum struck more or less diagonally

across those seas from their northern termini to the entrances of the

straits between the islands, thus lacing the seas in the way a sail is

rolled to its spar. From the exact manner in which they connected with

the light-region canals they proved the two to be part and parcel of

one system, which in its extension was planet-wide and therefore

proportionately important. Whatever of strange interest the curious

characteristics of the canals themselves suggested was now greatly

increased by this addition; for the solidarity of the phenomenon

affected the cogency of any argument derived from it.

In 1894 only the dark areas of the southern hemisphere were found to be

thus laced with lines. For then so great was the tilt of the planet’s

south pole toward the earth, that while those zones were well displayed

the dark patches of the northern hemisphere were more or less hull-down

over the disk’s northern horizon.

Contrast was the open sesame to their detection. When the _maria_ show

dark, the lines are lost in the sombreness of the background. As the

maria lighten the lines come out. Such was amply witnessed by the

effect in 1894 and 1896. In 1894 I found it impossible to perceive

them, except where the Padargus crossed Atlantis, for the hue of the

_maria_ themselves was then very dark. In 1896, on the other hand, I

saw them without difficulty. What is also of interest: so soon as seen

they appeared small, without haziness or distention.

As the oppositions succeeded one another the northern regions rose into

view, and with their appearance came the detection in them of the same

phenomena. No large dark areas like the diaphragm exist there, but the

smaller patches of blue-green which bestrew them proved to be similarly

meshed. At first canals were evident upon their peripheries, contouring

them about; then the bodies themselves of the patches showed

grid-ironed by lines.

The Mare Acidalium with its adjuncts, the Lucus Niliacus on the south

and the Lacus Hyperboreus on the north, thus stood out in 1901. On a

particularly good evening of definition at the end of May, the Mare

suddenly made background for a sunburst of dark rays, six of them in

all radiating from a point between it and the Lacus Hyperboreus.

Considering how sombre the Mare was at the time, this was as remarkable

a vision as it was striking to see. Although at the moment the sight

was of the nature of a revelation, these lines have been amply verified

since, as the Martian season has proved more propitious.

Similar decipherment has befallen all the other patches of blue-green

in the northern hemisphere; these having shown themselves first

circumscribed and then traversed by canals. Interesting instances were

the Wedge of Casius and the Propontis. These markings, first perceived

years ago as mere patches of shading, then partially resolved by

Schiaparelli, now stood revealed as a perfect network of lines and

spots. So many of both kinds of their detail occupied the ground that

to identify them all was matter of exceeding difficulty. The outcome is

shown in the diagrammatic representations opposite and on page 256.

These drawings disclose better than any description the mass of detail

of which the patches are in reality composed, and serve to convey an

idea of the complexity involved. If the general canal system seems

intricate, here is something which exceeds that as much again.

[Illustration: The Propontis, 1905.]

The extension in this manner of the curious triangulation of the light

areas into and through all the dark areas as well, by thus spreading

the field of its operations over both terranes complexioned so unlike,

greatly increases the cogency of the deduction that this detail is of

later origin than the background upon which it rests. That the mesh of

lines covers not only the ochre stretches of the disk, but the

blue-green parts as well, makes it still more certain that it is not a

simple physical outcome of the fundamental forces that featured the

planet’s face. For in that case it could not with such absolute

impartiality involve both alike. Thus here, again, we find

corroboration by later observations of what earlier ones established.

A last link in the chain of canal sequences remains to be recorded.

Just as the lines in the dark regions continued those in the light, so

they themselves turned out to be similarly prolonged and in no less

suggestive a manner. For when the north polar zone came to be

displayed, canals were evident there, continuing those in the other

zones and running at their northern ends into dark spots at the edge of

the polar cap. Here, then, we have the end of the whole system, or more

properly its origin, in the polar snows. The significance of this will

be seen from other phenomena, to a consideration of which we now

proceed.

CHAPTER XX

OASES

Next to be caught of the details of this most curious network that

meshes the surface of Mars was a set of phenomena stranger even than

the lines; to wit, dark round dots standing at their intersections.

More difficult to make out than the lines, they were in consequence

detected thus later by fifteen years. Once discovered, however, it

became possible to trace their unconscious recognition back in time.

Thus Schiaparelli told the writer in 1895, apropos of those found at

Flagstaff, that he had himself suspected them but could not make sure.

Some of them stand figured in his _Memoria Sesta_ dealing with the

opposition of 1888, but not published till 1899. In such posthumous

recognition, as one may call it, the spots repeated the history of the

canals. For Schiaparelli had himself pointed out a similar preconscious

visioning of the canals in the delicate pencilings of Dawes and the

streaks of Lockyer, Kaiser, and Secchi, now translatable as

representing the Phison, the Euphrates, and half a dozen other canals

imperfectly seen. That both the canals and the oases were thus sketched

before they were seen well enough to be definitely discovered is to an

unprejudiced mind among their strongest credentials to credit.

Nor was Schiaparelli the sole person thus to get proof before letter.

One of their very earliest portrayals appears in a drawing by Otto

Boeddicker, made on December 26, 1881, where the Pseboas Lucus is

clearly represented. In a still more imperfect manner some of the spots

had been adumbrated and their shadows drawn long before that. Thus they

may be deciphered as the cause of patches drawn by Dawes in 1864,

though none of them were in any definite sense detected till 1879, and

only then so ill defined that their true character was not apparent. As

patches they are still commonly seen at observatories where the

observational conditions are not of the best and the study of the

planet not systematically enough pursued to have them disclose their

true shape and size.

The history of their detection is resumed in the experience of the

individual observer. During the course of my own observations I have

had occasion to notice the several stages in recognition of the spots

which have marked their chronologic career. As with the lines, three

stages in the appearance of the spots may be remarked: first, where the

scattering of the rays is so wide that dilution prevents anything from

being seen; second, where the commotion being less the object appears

as a gray patch; and third, where in comparative quiet it condenses

into a black dot. For the two former our own air waves are to blame. In

coursing waves of condensation and rarefaction they spread the image of

the spot as they do that of the canal. Then as the currents calm the

spot shrinks to its normal proportions, and in so doing darkens in

consequence of being less widely diffused. Thus the evolution in

perception which may take place in the course of an hour for a

particular observer represents exactly what has occurred in the person

of the race by the improvement in observational methods and sites.

That the spots, although wider than the canals, remained longer hidden

from human sight, is due to the optico-physic fact that a tenuous line

may be perceived _owing to its length_ when a dot of the same diameter

would be invisible. Summation of impressions is undoubtedly the cause

of this. The mere fact that a row of retinal cones is struck, although

each be but feebly affected, is sufficient to raise the sum total into

the sphere of consciousness.

In the second stage of their visibility, the spots are in danger of

mistake with the smaller true patches of sombre hue which fleck the

northern hemisphere of the planet and from which they differ totally in

kind, totally so far as our present perception goes. Such true patches

consist of a groundwork of shading, upon which, indeed, are superposed

the usual network of lines and spots. Prominent as instances of them

are the Trivium Charontis, the Wedge of Casius, and the Mare Acidalium.

With patches of the sort the spots proper must not be confounded.

Close treading on the heels of the detection of lines athwart the seas

came the recognition of spots there likewise. At the opposition of

1896-1897 the number was added to; and so the tale has been steadily

increased. Their number as found at Flagstaff up to the present time,

that is, to the close of the opposition of 1905, is 186; of which 121

lie in the light regions, 42 in the dark areas of the southern

hemisphere, and 23 in the smaller sombre patches of the northern zones.

From their relationships and behavior it became apparent that the spots

were not lakes but something which answered much more nearly to oases.

Of the spots three kinds may be distinguished: the large, the little,

and the less, if by the latter term it may be permitted to denote what

has but collateral claim to be included and yet demands a certain

recognition. For though not spots like the others, the members of the

third class have certain traits in common with them while differing

radically in others.

To the kind called large belong the greater number of spots so far

found upon the disk. They are large only by comparison with the little.

For they measure according to my latest determinations but seventy-five

or one hundred miles in diameter; on the planet some two degrees

across. Sizable black pin-heads, it is their tone that chiefly catches

the eye, for they are commonly the darkest markings on the disk.

Against the ochre stretches they appear black, and even in the midst of

the dark areas they stand out almost as much contrasted with their

surroundings as these do with the light regions themselves. About a

hundred and forty are now known. Those in the light areas were

discovered first; those in the dark regions being harder to see.

Of this first kind are such spots as the Pseboas Lucus, the Aquae

Calidae, the Lacus Phoenicis, and the Novem Viae; or, in English, the

Grove of Pseboas, the Hot Springs, the Phœnix Lake, and the Nine Ways,

to mention no more. That they bear dissimilar names implies no

dissimilarity in structure. The phenomena are all remarkably alike, and

clearly betoken one and the same class of objects; differing between

themselves at most in size and importance.

In form they all seem to be round. They certainly appear so, and were

it not that retinal images of small areas tend to assume this shape

might implicitly be credited with being what they seem. The reason for

optical circularity probably resides in the shape of the retinal cones

and in their patterning into a mosaic floor. So that unless a

sufficient number of cones be struck the image takes on to

consciousness a roughly circular figure—whether it be so in fact or

not. In the present case, however, they seem to be too well seen for

self-deception of the sort.

The little are distinguished from the large by being pin-points instead

of pin-heads. They are most minute; from fifteen to twenty-five miles

in diameter only. That anything except size distinguishes the two apart

is from their look improbable. In color or rather tone,—for

distinctive color is of such minute objects unpredicable,—they would

seem to be alike. Such is also the case with their distribution and

detail association.

[Illustration: Fons Immortalis, June 19.]

To the second class belong the Fons Juventae,—Schiaparelli’s Fountain

of Youth,—the Fons Immortalis in Elysium in 1905, and the Gygaea

Palus, besides many more. These are all pin-points, just upon the limit

of vision, and noteworthy chiefly for being visible at all. All those

detected so far lie not very distant from the equator, which may or may

not be a matter of accident. It is not one of perception, since this

part of the planet was not the best place for observation at the time

they were discovered. To make out one of these little dots is a

peculiarly pleasing bit of observation, as it requires particularly

good definition. One might almost take them for fly-specks upon the

image did they not move with the disk. They have no perceptible size

and yet are clearly larger in diameter than the canals which run into

them; which proves how very slender the latter must be.

Very early in the detection of the spots it became evident that they

were not scattered haphazard over the surface, but that on the contrary

they were never found except at the meeting-points of the lines. From

this it must not be supposed, as has been done, that the spots are

merely optical reinforcements of the lines at their crossings due to

the more crowded character there of the lines themselves. That they are

not such is demonstrated by the existence of crossings where, either

temporarily or permanently, none appear; which shows that they are far

too well seen for any such illusion about them to be possible. At these

crossings the lines traverse one another without thickening, whether

they be single or double lines. The spots, on the other hand, are much

wider than the lines, giving a beaded look to the threads. In short,

they are the knots to the canal network. All the more important

junctions are characterized by their presence. Such starred junctions

are not confined to the ochre regions; they dot the light and the dark

areas with equal impartiality, thus showing themselves to be

independent of the nature of the ground where large stretches of

country are concerned. On the other hand, they appear to be unusually

numerous in the smaller, isolated, dark areas of the northern

hemisphere, such as the Trivium, the Mare Acidalium, the Propontis, and

the Wedge of Casius. Here they crowd; and one cannot avoid the

inference that their plentifulness in these regions is not due to

chance.

[Illustration: _Utopia regio—1903._]

To the large spots, those of the first class, fall the places of

intersection of the largest and most numerous canals, while the little

spots make termini to fainter lines, ones that bear to them a like

ratio of unimportance. Spots and lines are thus connected not simply in

position but in size. The one is clearly dependent on the other, the

importance of the centre being gauged by the magnitude of its

communications.

From the fact of association we now pass to the manner of it, which is

quite as remarkable. The position of the spot relative to its tributary

canals depends upon the character of the connecting lines. If the canal

be single it runs, so far as may be judged, straight into the middle of

the oasis, or, in other words, the oasis is symmetrically disposed

about its end. This is true of the greater number of the large spots

and of all the little ones, since the latter have as connections only

single canals.

In the case of a double canal arriving at a spot, a different and most

curious dependence is observable. This fact I first noticed in a

general way at the opposition of 1896-1897, the initial appearance of

it being presented on September 30, 1896, by the Coloe Palus and the

Phison. It was again visible in the case of the spots in the Trivium at

the time the canals leading to that place doubled in March, 1897. But

the exact nature of the phenomenon was not fully appreciated till 1903,

when the thing was seen so well as to appear cut on copper plate. It

was this: the spot is exactly embraced between the two arms of the

double canal. It is, moreover, seemingly perfectly round and just fits

in between the parallel lines. The Ascraeus Lucus was the first spot

that showed thus in association with the double Gigas. Others followed

suit in so showing, several specimens presenting themselves so well as

to leave no doubt of the precise connection. The sight presented by

such a spot and its incasing double is a beautiful bit of detail,

perhaps the most beautiful so far to be seen upon the Martian disk. The

distinctness with which it stands out on occasion suggests a steel

engraving, and shows how clear-cut the Martian features really are when

our own air ceases from troubling and allows them to be at rest.

Incidentally, we may note that this phenomenon alone serves to disprove

the diplopic theory of the production of the double canals. For if a

double were a single line seen out of focus, any spot upon it should be

doubled too.

[Illustration: _Ascraeus Lucus and Gigas.—March. 2. 1903._]

It may seem to the reader as if what was seen in 1903 was but an

unimportant advance over the observed phenomena of 1896-1897. Not so,

however. For with the earlier instances it was not possible to be sure

of the precise limits of the spot with regard to the double. The Coloe

Palus, on the one hand, did not fill all the space apparently between

the double Phison; while the Lucus Ismenius more than did so with the

double Euphrates. To have set down the different appearances to

insufficient definition would have been a great mistake, as subsequent

observation has served to show. The Lucus Ismenius instances this. In

1896-1897 it was seen terminating the Euphrates, blocking all the space

between the two lines and extending a little upon either side of them.

Now, from its appearance in 1901 it was evident that the effect had

been produced by twin spots lying along the Deuteronilus, the axis

joining them being perpendicular to the Euphrates. In 1903 the relation

was still better explained by what appeared then, when not only did the

two spots stand out, but the Euphrates showed with a line running

centrally into each.

Although originally seen by Schiaparelli as a single spot and so at

first seen by me, better acquaintance with the disk disclosed to both

observers its really dual character. As this pair has persisted through

all three of the most recent oppositions, it seems fairly certain that

it is always of this character, and more fitting, therefore, to give it

the plural appellative. This is the single instance of a double oasis.

There are many that lie close together and might be taken as such; but

this is the only one where the connection is intrinsic. According to

measures of the drawings of 1905 extending through six presentations,

the distance between the twin oases is 4°.2.

Their relation to the canals which run into them is of the most

complicated description and of the most suggestive character. For to

the twin spots converge no less than seven double canals, one

wedge-shaped pair and three single canals, a most goodly number of

communication lines. Four of the double canals run into the oases with

one line to each; these canals are the Astaboras, the Naarmalcha, the

Euphrates, and the Hiddekel. Three doubles, the Protonilus, the

Djihoun, and the Deuteronilus, embrace the oases between their two

lines, while, in the singles, the canal connects with one or other of

the twins, as the case may be.

Now, there is method as to which of the doubles shall straddle, which

embrace, the two Ismenii. Those which leave the place parallel or

nearly so to the direction joining the Luci, inclose them both; those

of which the setting forth is at an angle to this direction depart,

each line of the pair, from the eastern and the western spot

respectively.

[Illustration: Peculiar association of the Luci Ismenii with double

canals.]

Consider, now, the disposition of these seven pairs of lines. All of

them lie in one semicircle about the Luci, beginning with the

Protonilus on the east and ending with the Deuteronilus on the west.

Furthermore, all follow approximately arcs of great circles, except the

Djihoun, and all send one of their twin lines to one Lucus, one to the

other. The data are enough to make this statement possible. Although

the west line of the Naarmalcha has not been caught entering its oasis,

the east one has been seen to enter the other, and the width of the

double shows that the west one must enter the corresponding spot. In

the case of the Astaboras the double has only been observed as far as

the Vexillum, but the south line has continued on to the west Ismenius,

and here again the width makes it certain that were the canal double

throughout, the other line must enter the east Ismenius. From the base

line of the Proto-Deuteronilus the inclinations of the seven pairs are

as follows:—

Protonilus 0° Due East

Astaboras 40° North of East

Naarmalcha 70° North of East

Euphrates 80° North of West

Hiddekel 55° North of West

Djihoun 0° North of West

Deuteronilus 0° Due West

Now, the width between the two lines of the four canals to the east

increases regularly from the Protonilus round; the Protonilus being the

narrowest double, the Astaboras the next, the Naarmalcha the next, and

the Euphrates the widest. And from the width between the twin oases, it

would seem that they severally enter the centres of them. What takes

place in the case of the Hiddekel, which is wider than its tilt would

imply, and in the Djihoun, which is narrower, is not so clear. But that

they enter the oases in some place is certain.

[Illustration: _Lucus Ismenius. March 1903._]

The spots make common termini for all the canals of a given

neighborhood. In other words, canals converge to the places occupied by

the spots and do not cross haphazard according to the laws of chance.

Only one instance exists where a spot fails to gather to itself the

whole sheaf of canals and even there it collects all but two. This

anomaly is the Pseboas Lucus. The peculiarity of this oasis is that it

lies not on, but just off, the Protonilus. That it does so is exceeding

curious, considering that it is the sole example of such extra-canaline

position. Strictly speaking, it is not the Protonilus but the point

where the Protonilus turns into the Nilosyrtis to which it stands thus

neighboringly aloof. And this may explain the anomaly. For the

Nilosyrtis has not the full geometric regularity of the normal canal,

and seems to have been a more or less fundamental feature of the region.

For the rest, the Lucus has the form and possesses the canal

connections appropriate to its state. It is apparently round, and lies

between the twin lines of the Phison and also between those of the

Vexillum.

Not far from the Pseboas Lucus are to be found all the examples of the

third class of spots; for so far they have not been observed outside of

Aeria, a region peculiarly peopled by double canals. With double canals

they are necessarily associated, inasmuch as they consist of shading in

the form of a square or parallelogram, filling the deltas between two

pairs that cross. Thus have shown the Coloe Palus at the crossing of

the double Phison with the double Astaboras, and the Juturna Fons where

the double Sitacus traverses the double Euphrates.

At these same places a fourth kind is sometimes noticeable: a

four-square set of pin-points or a two-square set of the same at the

corners of the line-made parallelogram. This kind may well be

synchronous with the third, though it has only been noticed at

consecutive presentations. The third, however, has no observed

dependence upon the first or second classes. And this serves to make

more probable the true objectivity of the circular and the square

figures respectively shown by each.

The spots apparent in the dark regions do not appreciably differ in

either size or shape from the bulk of those visible in the light.

Equally with them they seem to be round, small, and nearly black. They

would seem, too, in the great diaphragm—or larger contiguous sombre

region—to be equally plentifully distributed.

CHAPTER XXI

CARETS ON THE BORDERS OF THE GREAT DIAPHRAGM

Functionally related to the canal system, and yet in look and location

contrasted with its other details, is a further set of markings,

detected by me in 1894, and reseen at subsequent oppositions since,

along the north border of the southern seas. They lie upon what used to

be thought the continental coastline, the fringing edge of that almost

continuous band of shading that belts the Martian globe throughout the

southern subtropic zone and called by Schiaparelli the great diaphragm.

The terrane lends itself to the appellative, forming, as it does, a

dark dividing strip of country between the brilliant reddish-ochre

hemisphere on the north and the half-toned islands to the south of it.

By Schiaparelli it was thought to be one long Mediterranean, and though

its marine character is now disproved, that it lies lower than the

bright ochre regions is likely. To this difference of level is probably

due the peculiar phenomenon which there manifested itself to careful

scrutiny in 1894. For it was there only that it occurred.

The phenomenon in question consisted of nicks in the coastline, of

triangular shape and filled with shading. They occurred at intervals

along it and were of the general form of carets, such marks as one

makes in checking items down a list. Their position was always where a

canal debouched from the diaphragm upon its career across the open

continent. The canal itself was by no means necessarily visible. On the

contrary, at first it was usually absent. Such was the case with those

marking the departure-points of the Phison and Euphrates and of the

Amenthes and Lethes, which appeared, without being well defined, from

the moment the planet came to be scanned.

One by one these carets stood out to view, punctuating the points where

canals later were to show or terminating those that already existed.

Strung thus with them at intervals was the whole coastline of the

diaphragm, beginning with the Mare Icarium and stretching round through

the Mare Tyrrhenum, Mare Cimmerium, Mare Sirenum, and Mare Erythraeum

to the Mare Icarium again. As the planet got nearer to the earth their

peculiar shape began to define itself, and it was again in the case of

those giving origin to the Phison and Euphrates that the recognition

came first. What had appeared earlier simply as a spot now stood out as

two triangular notches, indenting the coast and giving exit at their

apices, the eastern one to the Phison, the western to the Euphrates.

These were the things, then, that had constituted the Portus Sigaeus of

Schiaparelli.

Commonly the carets lie at the bottom of well-marked bays, as, for

example, those terminating the Syrtis Minor and the Sinus Titanum. But

frequently they are placed in the very midst of a long and otherwise

unaccented coast, as is the case in mid-course of the Mare Cimmerium

and the Mare Sirenum. Yet in no instance is the thing unassociated with

a canal. In every case one or more canals leave the caret for their

long traverse down the disk.

This is not their only canal connection. When the canals in the dark

regions came to be discovered, each of them was found by me, as nearly

as difficult observations would permit, to be associated with the caret

upon its other side. Thus the lacing of the Mare Cimmerium and Sirenum

used them as its reeving-points. Similarly those at the mouths of the

Phison and Euphrates did duty likewise to the Maesolus and the Ion. In

such manner the carets stood in dual relation to canals; subserving a

purpose to the light-region canals on the one hand and to the

dark-region ones on the other. In a way the caret, then, holds the same

position toward the canals that do the spots in the light or dark

regions. Like them it is a canal-distribution point. Unlike them,

however, in shape it is triangular instead of round, and we are piqued

to inquire to what cause it can owe its different contour. The answer

seems to lie in the character of the locality, not simply in its

complexion. For the spots in both the northern and the southern dark

patches are as circular as those standing in the light, whether they

lie in the centre or upon the edges of them. The edges of the northern

patches, however, and the other sides of the southern ones do not

present the clear-cut character of the northern coast of the diaphragm.

Where they seem to be definitely bounded they are so by darker canals.

This hints that their contours are not defined by antithesis of level,

while that of the northern coast of the great diaphragm is. Difference

of altitude is then concerned in their constitution; the canal system

here falls to a lower level, and these triangular spots instead of

round ones are the result. Topographic only, such explanation leads the

way to a more teleologic one, and serves even on first acquaintance to

stir curiosity to some satisfying cause.

Suggestive in several ways for its resemblance to the carets is another

detail not far distant from the Portus Sigaei, the twin-forked Sabaeus

Sinus. Curiously enough, this feature of Mars, which has been well

known and recognized ever since the eagle-eyed Dawes detected it more

than forty years ago, proves to be a sort of connecting link between

the main markings and the details of more modern detection. The

twin-forked Sabaeus Sinus, as its name implies, is of the form of a

double bay; was considered to be one in fact so long as the _maria_

were held to be seas. It straddles the point of land which, called the

Fastigium Aryn, has been taken for the Greenwich of Martian longitudes.

Each ‘bay’—not in truth a bay at all—indents the ochre in an acute

triangle, from the tip of which many canals proceed like the rays of a

fan from a holding hand. Both tips are darker than the main body of the

dark _mare_ from which they proceed. They thus recall in general

character the carets. They further reproduce specifically the Portus

Sigaei, for they give origin to two doubles, the Gihon and the

Hiddekel, in exactly the same manner that the two nicks of the Portus

Sigaei do to the Phison and Euphrates. Nor are their tips much farther

apart than those of the Portus, five degrees measuring the spread of

the one and four degrees that of the other respectively; the reason for

their earlier discovery lying in their greater size. They thus perform

the same office as the Portus Sigaeus, are quite comparable to it in

width, and differ in shape only as a larger and more acute triangle

differs from a smaller and blunter one. Undreamt of by Dawes and

unheeded since, they were the first hint to the world of the duality

which forms so strangely pervasive a feature of the canal system of the

planet.

Thus the carets stand connected with the canals quite as intimately as

the oases but in a significantly different manner. For, in addition to

their intermediary standing between the light regions and the dark,

their relation to the doubles is peculiar. An instance is offered by

the double Euphrates and another by the Ganges. The Euphrates, as we

saw in Chapter XVIII, leaves the Portus Sigaei at the south, one line

leaving each caret centrally, so that each caret is concerned only with

its own line and has no connection with its fellow. At their northern

ends both lines have similarly each its own Lucus Ismenius. The like

seems to be true of the Ganges. Similarly the twin Titan, have each its

own. Such twin duty in the matter of doubles seems to be the rule with

the carets, even more so than with the oases; and this is probably from

the fact that the coastline is of more limited extent than the interior.

Altogether the carets offer to our inspection glosses in finer print

upon the general text of the canals. Thought upon what they show takes

us a step farther toward the solution of the strange riddle of this

other world, a riddle which he who runs may not read, still less scout,

and which only reasoning, without prejudice or partiality, can unravel.

CHAPTER XXII

THE CANALS PHOTOGRAPHED

Photography holds to-day a place of publicity in the exposition of the

stars. Directed by Draper to the heavens thirty-four years ago, the

camera recorded then the first picture ever taken of the moon. From

this initial peering into celestial matters, practice has progressed

until now the dry plate constitutes one of the most formidable engines

in astronomic research. Not most effectively, however, in the field

which might have been predicted. Beautiful as the lunar presentment

was, as a presentiment of what was coming, it pointed astray. For it is

not in lunar portrayal, superbly as its crater walls in crescent

chiaroscuro or its crags that cast their tapering shadows athwart the

dial of its plains stand out in the latest photographs of our

satellite, that the camera’s greatest service has since been done.

Impressive as they are, these pictorial triumphs are chiefly popular,

and appeal on their face to layman and scientist alike. Not in the

nearest to us of the orbs of heaven, but in the most remote has

celestial photography’s most prolific field been found to lie. Its

province has proved preëminently the stars, especially the farthest

off, and that star-dust, the nebulæ, from out of which the stars are

made. Reason for this explains at once its efficiency and its

limitations.

Its rival, of course, is the eye. It is as regards the eye that its

comparative merits or demerits stand to be judged. Now, thus viewed,

its superiority in one respect is unquestionable; it simply states

facts. But though it cannot misinform, it can color its facts by giving

undue prominence to the effect of some rays and suppressing the

evidence of others, so that its testimony is not, it must be

remembered, always in accord with that of human vision. Speaking

broadly, however, it is so little complicated a machine as to register

its results with more precision than the retina. The evidence of the

camera has thus one important advantage over other astronomic

documents: it is impersonally trustworthy in what it states. Bias it

has none, and its mistakes are few. Imperfections, indeed, affect it,

but they are of purely physical occasion and may be eliminated or

accounted for as well by another as by the photographer himself.

In trustworthiness, then, so far as it goes, it stands commended; not

so much may be said of its ability. This depends upon the work to which

it is put. In certain lines it asserts preëminence; in certain others

it is so far behind as to be out of the race. The reason for both is

one and the same, for, as the French would say: It has the faults of

its quality. The very trait that fits it for one function, bars it from

the other. This excellence is that by which the tortoise outstripped

the hare,—a plodding perseverance. Far less sensitive than the retina

the dry plate has one advantage over its rival,—its action is

cumulative. The eye sees all it can in the twentieth of a second; after

that its perception, instead of increasing, is dulled, and no amount of

application will result in adding more. With the dry plate it is the

reverse. Time works for, not against it. Within limits, themselves

long, light affects it throughout the period it stands exposed and,

roughly speaking, in direct ratio to the time elapsed. Thus the camera

is able to record stars no human eye has ever caught and to register

the structure of nebulæ the eye tries to resolve in vain.

Where illumination alone is concerned the camera reigns supreme; not so

when it comes to a question of definition. Then by its speed and

agility the eye steps into its place, for the atmosphere is not the

void it could be wished, through which the light-waves shoot at will.

Pulsing athwart it are air-waves of condensation and rarefaction that

now obstruct, now further, the passage of the ray. By the nimbleness of

its action the eye cunningly contrives to catch the good moments among

the poor and carry their message to the brain. The dry plate by its

slowness is impotent to follow. To register anything, it must take the

bad with the better to a complete confusion of detail. For the

air-waves throw the image first to one place and then to another, to a

blotting of both.

All of which renders the stars, where lighting counts for so much and

form for so little, the peculiar province of celestial photography.

With the study of the surfaces of the planets the exact contrary is the

case. With most of them illumination is already to be had in abundance;

definition it is that is desired. What succeeds so excellently with the

stars is here put to it to do anything at all. At its best, the camera

is hopelessly behind the eye when it comes to the decipherment of

planetary detail. To say that the eye is ten times the more perceptive

is not to overstep the mark. To try, therefore, here to supplant the

eye by the camera is time thrown away.

Of scant importance to the expert in such matters as Mars, there is a

side of the subject in which service might be hoped of it: that of

elementary exposition. Congenitally incapable of competing with the eye

in discovery, the most that, by any possibility, could be looked for

would be a recording of the coarser details after the fact. For this

reason it had long been a purpose at Flagstaff to photograph some at

least of the canals. But the project seemed chimerical. To get an image

suitable at all some seconds of exposure would be required, and during

such time the shifting air-waves would blur the very detail desired to

be got. It was a problem of essential premises mutually annihilative.

The more the would-be photographer should avoid the one; the more he

would fall into the other.

Nevertheless the thing was tried in 1901. In 1903 the subject was taken

up by Mr. Lampland, then new at the observatory. The results were

better than those of two years before, the images more clear-cut but

still incommunicable of canals. Still they were satisfactory enough to

spur to increased endeavor, and during the following interopposition

preparations were made to grapple with the planet as successfully as

could be devised at its next return. This happened in May, 1905. It

then showed a disk only 17′′ in diameter, or 1/120 that of the

moon,—and this disk Mr. Lampland attacked with the 24-inch and a

negative amplificator that increased the focal length of the former to

143 feet. At such focus the planet’s image was received upon the plate.

Everything that could conduce to success had been put in requisition.

To this end of better definition the color curve of the objective was

first got, and for it a special color screen constructed by Wallace. In

spite of its name no achromatic is so in fact, but brings rays of

different tint to different focus. The color curve shows where these

severally lie, and the color screen, a chemically tinted piece of

glass, is to absorb all those which would blur the image by having a

different focus from the ones retained. Next, all manner of plates were

tried. For in these again it was necessary to reconcile two

contradictory characters, a rapid plate and a well-defining one. For

the coarser the grain the speedier the plate; and coarse grain

disfigures the detail. Both qualities on so small an image were

obligatory and yet both could not be got. Then the clock had to be as

smooth-running as possible. So by a suggestion of Mr. Cogshall’s one

was obtained that filled this requisite, a new form of conical

pendulum. Upon this a further refinement was practiced. Ordinarily

clockwork is timed to follow the stars; this was altered to follow the

planet, and so keep it more nearly motionless while its picture was

being taken. Then the device of capping down the telescope to suit the

air-waves, which had been found so effective to the bringing out of

fine detail, was put in practice. Lastly, all developers were tried,

and those found suited to the finest work were used.

Many pictures were taken on each plate one after the other, both to

vary the exposure and to catch such good moments as might chance. Seven

hundred images were thus got in all; the days of best definition alone

being utilized. The eagerness with which the first plate was scanned as

it emerged from its last bath may be imagined, and the joy when on it

some of the canals could certainly be seen. There were the old

configurations of patches, the light areas and the dark, just as they

looked through the telescope, and never till then otherwise seen of

human eye, and there more marvelous yet were the grosser of those lines

that had so piqued human curiosity, the canals of Mars. He who ran

might now read, so that he had some acquaintance with photography. By

Mr. Lampland’s thought, assiduity, and skill, the seemingly impossible

had been done.

After the initial success was thus assured, plates were taken at other

points around the planet and other well-known features came out;

“continents” and “seas,” “canals” and “oases,” the curious geography of

the planet printed for the first time by itself in black and white. By

chance on one of the plates a temporal event was found registered too,

the first snowfall of the season, the beginning of the new polar cap,

seen visually just before the plate happened to be put in and

reproduced by it unmistakably. Upon the many images thirty-eight canals

were counted in all, and one of them, the Nilokeras, double. Thus did

the canals at last speak for their own reality themselves.

PART III

THE CANALS IN ACTION

CHAPTER XXIII

CANALS: KINEMATIC

So far in our account of the phenomena we have regarded the lines, the

spots, and everything that is theirs solely from the point of view of

their appearance at any one time. In other words, we have viewed them

only from a static standpoint. In this we have followed the course of

the facts, since in this way were the canals first observed. We now

come to a different phase of the matter,—the important disclosure,

with continued looking, that these strange things show themselves to be

subject to change. That is, they take on a kinematic character. This at

once opens a fresh field of inquiry concerning them and widens the

horizon of research. It increases the complexity of the problem, but at

the same time makes it more determinate. For while it greatly augments

the number of facts which must be collected toward an explanation of

what the things are, these once acquired, it narrows the solution which

can apply to them.

The fact of change in the Martian markings forces itself upon any one

who will diligently study the planet. He will be inclined at first to

attribute it to observational mistakes of his own or his predecessor’s

making, preferably the latter. But eventually his own delineations will

prove irreconcilable with one another, and he will then realize the

injustice of his inference and will put the cause, where indeed it

rightly belongs, on the things themselves. Confronted by this fact he

will the more fully appreciate how long and systematic must be the

study of him who would penetrate the planet’s peculiarity. Just as the

recognition of something akin to seasonal change came to Schiaparelli,

because of his attending to the planet with an assiduity unknown to his

predecessors; so it became evident that to learn the laws of these

changes and from them the meaning of the markings, there was necessary

as full and as continuous a record of them as it was possible to

obtain. For this end it was not enough to get observations from time to

time, however good these might be, but to secure as nearly as might be

a complete succession of such, day after day, month after month, and

opposition after opposition. The outcome justified the deduction. And

it is specially gratifying to realize that to no one have the method

and the results thus obtained appealed with more force than to

Schiaparelli himself.

Perseverance in scanning the disk long after the casual observer had

considered it too far away for observational purposes, resulted in

Schiaparelli’s detection of the canals, and this through a

characteristic of theirs destined to play a great part in their

history, their susceptibility to change. He tells us in his _Memoria I_

how Aeria and the adjoining regions showed blank of any markings while

the planet was near in 1877 and the disk large and well shown, and then

how, to his surprise, as the planet got farther away and the disk

shrank, lines began to come out in the region with unmistakable

certainty. Thus to the very variability which had hidden them to others

was due in Schiaparelli’s hands their initial recognition.

Flux affecting the canals was apparent from the outset of my own

observations. No less the subject of transformation than the large dark

regions was the network of tenuous lines that overspread them. At times

they were very hard to make out, and then again they were comparatively

easy. Distance, instead of rendering them more difficult, frequently

did the reverse. Nor was the matter one of veiling. Neither our own

atmosphere nor that of Mars showed itself in any way responsible for

their temporary disappearance. It was not always when our atmospheric

conditions were best that the lines stood out most clearly, and as to

Martian meteorology there was no sign that it had anything whatever to

do with the obliteration. Long before the canals were dreamt of,

veiling by Martian clouds or mist had been considered the cause of

those changes in the planet’s general features, which are too extensive

and deep-toned wholly to escape observation even though none too

clearly seen. It was early evident to me that they were not the cause

of general topographic change, and equally clearly as inoperative in

those that affected the canals. In short, nothing extrinsic to the

canal caused its disappearance; whatever the change was, its action lay

intrinsic to the canal itself.

On occasion canals in whole regions appeared to be blotted out. The

most careful scrutiny would fail to disclose them, where some time

before they had been perfectly clear. And this though distance was at

its minimum and definition at its best. Even the strongest marked of

the strange pencil lines would show at times only as ghosts of their

former selves, while for their more delicate companions it taxed one’s

faith to believe that they could ever really have existed. Illumination

was invoked to account for this, and plays a part in the effect

undoubtedly. For at plumb opposition the centre of the disk for two or

three years has shown less detail than before and after that event.

This is probably due not, as with the moon, to the withdrawal of

shadows, but to the greater glare to which the disk is then subjected.

But this is not the chief cause of the change.

Still more striking and unaccountable was the fact that each canal had

its own times and seasons for showing or remaining hid. Each had its

entrances upon the scene and its exits from it. What dated the one left

another unaffected. The Nilokeras was to be seen when the Chrysorrhoas

was invisible, and the Jamuna perfectly evident when the Indus could

scarcely be made out.

[Illustration: Showing seasonal change.

I.]

So much shows in the two drawings here reproduced. The increase of the

Ganges and the advent of the Chrysorrhoas are noticeable in the second

over the first.

[Illustration: Showing seasonal change.

II.]

Seasonal changes seemed the only thing to account for the phenomena.

And in a general sense this was undoubtedly the explanation. To learn

more about the matter, to verify it if it existed, and to particularize

it if possible, I determined to undertake an investigation permitting

of quantitative precision in the case. A method of doing this occurred

to me which would yield results deserving of consideration from the

amount of data upon which each was based and capable of being compared

with one another upon an equal footing from which relative information

could be derived. It seemed wise to determine from the drawings the

degree of visibility of a given canal at different seasons of the

Martian year, and then to do this for every important canal during the

same period of time. The great number of the drawings suggested this

use to which they might be put. For from a great accumulation of data a

set of statistics on the subject could be secured in which accident or

bias would be largely eliminated and the telling effect of averages

make itself felt.

To render this possible it was necessary that the drawings should be

alike numerous, consecutive, and extended in time. These conditions

were fulfilled by the drawings made by me at the opposition of 1903.

Three hundred and seventy-two drawings had then been secured, and they

covered between them a period of six months and a half. They were also

as consecutive as it was possible to secure. During a part of the

period the planet was seen and drawn at every twenty-four hours, from

April 5, namely, to May 26, or for forty-six consecutive days. Though

the rest of the time did not equal this perfection, no great gap

occurred, and one hundred and forty-three nights were utilized in all.

Furthermore, as these drawings were all made by one man, the personal

equation of the observer—a very important source of deviation where

drawings are to be compared—was eliminated.

But even this does not give an idea of the mass of the data. For by the

method employed about 100 drawings were used in the case of each canal,

and as 109 canals were examined this gave 10,900 separate

determinations upon which the ultimate result depended. That each of

these determinations was independent of the others will appear from a

description of the method itself on which the investigation was

conducted. To understand that method one must begin a little way back.

As the two planets, Mars and the Earth, turn on their axes the parts of

their surfaces they present to each other are constantly changing. For

a feature on Mars to be visible from a given post on earth, observer

and observed must confront each other, and, furthermore, it must be day

there when it is night here. But, as Mars takes about forty minutes

longer to turn than the Earth, such confronting occurs later and later

each night by about forty minutes, until finally it does not occur at

all while Mars is suitably above the horizon; then the feature passes

from sight to remain hidden till the difference of the rotations brings

it round into view again. There are thus times when a given region is

visible, times when it is not, and these succeed each other in from

five to six weeks, and are called presentations. For about a fortnight

at each presentation a region is centrally enough placed to be well

seen; for the rest of the period either ill-placed or on the other side

of the planet.

If a marking were always salient enough it would appear in every

drawing made of the disk during the recurrent fortnights of its

display. If it were weaker than this, it might appear on some drawings

and not on others, dependent upon its own strength and upon the

definition at the moment, and we should have a certain percentage of

visibility for it at that presentation. While if it changed in strength

between one presentation and the next, the percentage of its recording

would change likewise. Definition of course is always varying, but if

its value be noted at the time of each drawing this factor may be

allowed for more or less successfully. Making such allowance, together

with other corrections to produce extrinsic equality, such as the

planet’s distance, which we need not enter upon here, we are left with

only the marking’s intrinsic visibility to affect the percentages; that

is, the percentages tell of the changes it has successively undergone

and give us a history of its wax and wane.

From drawings accurately made it is possible to add to the accuracy of

the percentage by noting in each, not only the presence or absence of

the marking, but the degree of strength with which it is represented.

This was done on the final investigation in the present case, and it

was interesting to note how little difference it made in the result.

The longitude of each canal was known, and the longitude of the central

meridian of each drawing was always calculated and tabulated with the

drawing, so that it was possible to tell which drawings might have

shown the canal. Only when the position of the canal was within a

certain number of degrees of the centre of the drawing (60°) was the

drawing used in the result, allowance being duly made for the loss upon

the phase side. Each drawing, it should be remembered, was as nearly an

instantaneous picture of the disk as possible. It covered only a few

minutes of observation, and was made practically as if the observer had

never seen the planet before. In other words, the man was sunk in the

manner. Such mental effacement is as vital to good observation as

mental assertion is afterward to pregnant reasoning. For a man should

be a machine in collecting his data, a mind in coördinating them. To

reverse the process, as is sometimes done, is not conducive to science.

When the successive true percentages of visibility of a given canal had

thus been found, they were plotted vertically at points along a

horizontal line corresponding in distance from the origin to the number

of days after (or before) the summer solstice of the Martian northern

hemisphere. The horizontal distance thus measured the time while the

vertical height gave the relative visibility. The points so plotted

were then joined by a smooth curve. This curve reproduced the

continuous change in visibility undergone by the canal during the

period under observation. It gave a graphic picture of the canal’s

change of state. It seemed, therefore, proper to call it the canal’s

cartouche or sign manual.

In this manner were obtained the cartouches of 109 canals. Now, as the

presence or absence of any canal in any drawing was entirely

irrespective of the presence or absence of another, each such datum

spoke only for itself, and was an entirely independent observation. The

whole investigation thus rested on 10,900 completely separate

determinations, each as unconditioned by the others as if it existed

alone.

As every factor outside of the canal itself which could affect the

latter’s visibility was taken account of, and the correction due to it

as nearly as possible applied before the cartouches were deduced, the

latter represent the visibility of the canal _due to intrinsic change

alone_. In other words, they give not the apparent only but the real

history of the canal for the period concerned.

Important disclosures result from inspection of the cartouches. This we

shall perceive by considering what different curves mean in the case.

If the canal were an unchangeable phenomenon, for any reason whatever,

its cartouche would be a _straight line parallel to the horizon_ of the

diagram. This is evident from the fact that the visibility would then

never vary. If, on the other hand, it were waxing and waning, and the

wax or wane were uniform, the cartouche would be a straight line

_inclined to the horizontal_; rising if the canal were increasing,

falling when it decreased. Lastly, if the rate of change itself varied,

the cartouche would be a curve concave or convex to the line denoting

the time, according as the rate of change of the growth or decay grew

greater or less.

To see this the more clearly, we may set over against the cartouche the

canal character it signalizes:—

Cartouche. Character.

A horizontal straight line. Canal invariable.

A straight line tilted up on the right. Canal increasing steadily.

A straight line tilted up on the left. Canal decreasing steadily.

A curved line descending, concave from Canal decreasing, but more

above. and more slowly.

A curved line ascending, concave from Canal increasing, but more

above. and more rapidly.

A curved line descending, convex from Canal decreasing more and

above. more rapidly.

A curved line ascending, convex from Canal increasing more and

above. more slowly.

A curved line first descending, then Canal decreasing more and

ascending, concave from above more slowly to a minimum,

throughout. thence increasing

more and more rapidly.

A curved line first descending, then Canal increasing more and

ascending, convex from above more slowly to a maximum,

throughout. thence decreasing

more and more rapidly.

If the cartouche first falls and then rises, this shows the canal to

have passed through a minimum state at the time denoted by the point of

inflection; if it rises first and falls afterward, this betokens in the

same way a maximum. Thus the cartouches reveal to us the complete

history of the canals,—what changes they underwent and the times at

which these occurred. The cartouche, then, is the graphic portrayal of

the canal’s behavior. It not only distinguishes at once between the

dead and the living, as we may call the effect of intrinsic change, but

it tells the exact character of this change,—the way it varied from

time to time, the epoch at which the development was at its minimum or

its maximum for any given canal, and lastly, its actual strength at any

time, thus giving its relative importance in the canal system. For the

height of the curve above the diagrammatic horizon marks the absolute

as well as the relative visibility and enables us to rank the canals

between themselves.

Now, the first point it furnishes a criterion for is the real or

illusory character of the canals. If a line be due to illusion, whether

optical or physical, it can vary only from extrinsic cause, since it

has no intrinsic existence. If, therefore, all extrinsic cause be

allowed for, the cartouche of this ghost must needs be a _horizontal

straight line_. Even if the extrinsic factors to its production be

imperfectly accounted for, their retention could only cause systematic

variations from the straight line in all the lines, which would

themselves vary systematically, and these factors could therefore be

detected.

This criterion is absolute. Unless all the cartouches were

approximately straight lines, no illusion theory of any kind whatever

could explain the facts. Even then the lines might all be real; for

unchangeable reality would produce the same effect on the cartouches as

illusion. In the case therefore of horizontal straight line cartouches,

we should have no guarantee on that score of reality or illusion; but,

on the other hand, curves or inclined straight lines in them would be

instantly fatal to all illusion theories.

Turning now to the 109 cartouches obtained in 1903, the first point to

strike one’s notice is that all but three of them are curves and that

even these three must be accepted with a caveat. Here, then, the

cartouches dispose once and for all of any and every illusion theory.

They show conclusively that the canals are real objects which wax and

wane from some intrinsic cause.

The second result afforded by the cartouches is not of a destructive,

negative character,—however valuable the destruction of bars to

knowledge may be,—but of a constructive, positive one. It does not,

like the first, follow from mere inspection, but is brought to light

only by comparison of all the cartouches. In a positive way, therefore,

its testimony is as conclusive as it was in a negative direction. For

that 10,900 separate and independent data should result in a general

law of development through either conscious or unconscious bias, when

those data would have to be combined in so complicated a manner for the

result to emerge as is here the case, is impossible. Chance could not

do it and consciousness would require a coördinate memory, to which

Murphy’s nine games of chess at once would be child’s play.

Of the 109 canals examined 106 showed by their cartouches that they had

been during the whole or a part of the period in a state of change. But

the change was not the same for all. In some the minimum came early; in

others, late. Some decreased to nothing and stayed there; others

increased from zero and were increasing still at the time observations

closed.

Latitude proved the means of bringing comparative order out of the

chaos. When the canals were ranged according to their latitude on the

planet, a law in their development came to light. To understand it, the

circumstances under which the canals were presented must be considered

as regards the then season of the planet’s year. In 1903 the planet

passed on February 28 through the point of its orbit where the summer

solstice of the northern hemisphere occurs. One hundred and twenty-six

days later took place the first snowfall in the arctic and subarctic

regions, an event that denoted the beginning of the new polar cap; from

which date the snow there gradually increased. Its autumnal equinox the

planet did not reach till August 29. Now, the canals were observed from

thirty-six days before the summer solstice of the northern hemisphere

to one hundred and forty-seven days after that event. We may tabulate

the dates as follows:—

================+===========+================

DAY FROM | VERNAL | CORRESPONDING

SUMMER SOLSTICE | LONGITUDE | DATE ON EARTH

----------------+-----------+----------------

-30 | 77° | June 9

0 | 90° | June 22

+30 | 103° | July 6

+60 | 117° | July 20

+90 | 131° | August 4

+120 | 146° | August 20

+150 | 162° | September 5

================+===========+================

The vernal longitude is the longitude of the planet in its orbit

reckoned from the vernal equinox. From the table it appears that the

cartouches cover the development of the canals from about June 6 to

September 1 of the Martian northern hemisphere for the current but to

us undated year, _ab Marte condita_.

The 109 canals included all the more conspicuous canals on the planet

at that opposition, all those that lent themselves by the sufficient

frequency with which they were seen to a statistical result. They lay

spread all the way between the edge of the polar cap in latitude 87°

north to the extreme limit south, at which the then tilt of the north

pole toward the earth permitted of canal recognition. This southern

limit was in about latitude 35° south. Farther south than this vision

became too oblique, amounting as it did, with an adverse tilt of

twenty-five degrees to start with, to something over sixty degrees, for

detection of such fine markings to be possible. Between the two limits

thus imposed, by the perpetual snow on the one side and the

observational tilt on the other, the 109 canals were distributed by

zones as follows:—

=================+===============+===========

ZONE | LATITUDE | NUMBER OF

| | CANALS

-----------------+---------------+-----------

North Polar | 87° N.-78° N. | 1

Arctic | 78° N.-66° N. | 9

Sub-Arctic | 66° N.-51° N. | 9

North Temperate | 51° N.-37° N. | 11

North Sub-Tropic | 37° N.-24° N. | 18

North Tropic | 24° N.-12° N. | 21

North Equatorial | 12° N.- 0° N. | 14

South Equatorial | 0° N.-12° S. | 17

South Tropic | 12° S.-24° S. | 7

South Sub-Tropic | 24° S.-37° S. | 2

=================+===============+===========

As the latitude of a canal in the investigation was taken as that of

its mid-point, such being the mean value of its successive parts, the

latitudes about which information was obtained lay within the limits

given above, the most northern canal, the Jaxartes N having for its

mid-latitude 78° north, and the most southern, the Nectar, that of 27°

south.

The zones comprised each a belt of territory about thirteen degrees

wide, the first being less solely because in part occupied by the

permanent polar cap.

The curves of all the canals in a given zone have been combined into a

mean curve or cartouche for that zone; and then the cartouches for the

several zones have been represented and ranged according to latitude on

the accompanying plate. Consideration of these mean canal cartouches is

very instructive. In the first place not one of them is a straight

line, either horizontal or inclined. All are curves and, with the

exception of the top one, all show a minimum or lowest point during the

period under observation. From this point they rise with the time, or

to the right on the plate. A black star marks this minimum, and is

found farther and farther to the right as one goes down the plate; that

is, as one travels from the neighborhood of the arctic regions down to

the equator and then over into the planet’s southern hemisphere.

Drawing now a line approximately through the stars and remembering that

the minimum means the date at which the canal started to develop, we

see that the canal development began at the border of the north polar

cap and thence continued down the disk over the planet’s surface, as

far as observation permitted the surface to be seen, which was some

thirty-five degrees into the other hemisphere. This is the first broad

fact disclosed by the cartouches.

[Illustration: _MEAN CANAL CARTOUCHES_

P.L.]

Furthermore, the development took place at an approximately uniform

rate. This is shown by the fact that the line passing through the black

stars is approximately straight; for such straightness means that

progression down the disk as measured by the latitude bore throughout

the same ratio to the time elapsed.

Looking at them again we notice that the three topmost cartouches,

those of the north polar, arctic, and sub-arctic canals respectively,

dip at the right before the end of the observations, while the other

seven were still rising when those observations were brought to a

close. A reason for this, or at least a significant coincidence, is to

be found in the dotted line pendent from the top of the table and

labelled “First Frosts.” This dotted line denotes the date at which the

first extensive frost occurred in the polar regions; for even before

this time patches of white had appeared north of the Mare Acidalium,

denoting the on-coming of the cold. The frost did not last but came and

went and came again just as it does on earth, growing more insistent

and long-lived at each fresh fall. Its sphere of operation was confined

to the three zones in question. Even these zones it by no means

covered, merely blotching them in places with fungi-like patches of

frost. Beyond them south it never extended during the period of the

observations; indeed, it hardly entered the sub-arctic zone at all at

this very beginning of the polar winter. For it was only August 20

then. The coincidence of the isotherm as betrayed by the deposition of

frost with the dividing line between the canal-development curves that

dip down at this season and those that still continue to rise is

suggestive.

It becomes all the more so when the three cartouches are considered

seriatim. The most polewards, the north polar one, had sunk to zero

sometime before the first extensive frost occurred; the second, the

arctic, did so later than its northern neighbor, probably just before

the epoch in question; while the third, practically outside the zone of

deposition, was behind both the others in its descent. Inspection of

the drawings upon which the cartouches are based confirms an inference

deduced from this: that it was cold that killed, not frost that

covered, them, which was responsible for their obliteration. The

drawings show that the canals ceased to be seen before the white

patches were evident. Now this would be the exact behavior of

vegetation. It would be killed, turned brown by freezing, and so

rendered invisible to us against its ochre desert background, before

the cold had grown intense enough to cover that ground with a solid

white carpet of frost. At the opposition of 1905, however, the extreme

northern canals were visible after the snow had covered all the country

about them, being evident as lines threading the new cap.

These three cartouches furthermore show each a maximum, and what is

significant the maximum occurs later in time for each, according as the

zone lies remote from the pole. A red star marks this maximum and shows

that the time of greatest development for the three zones was

respectively:—

41 days after the summer solstice for the North Polar.

61 days after the summer solstice for the Arctic.

95 days after the summer solstice for the Sub-Arctic.

We now pass to the other curves, those that were unaffected by cold.

Though in these the minima themselves show the law of latitudinal

progression, the wavelike character of the advance is even better

disclosed by the curves. As the eye follows them down the page, the

advance of the wave to the right is plainly apparent. The slope of the

wave is much the same for all, implying that a like force was at work

successively down the latitudes.

It will be noticed next that in all the mean cartouches the gradient is

greater after the minimum than before it. The curves fall gently to

their lowest points and rise more steeply from them. Such profile

indicates that the effects of a previous force were slowly dying out

down to the minimum and that then an impulse started in to act afresh.

This explains the attitude of the canals that died out. In them the

effect of the old force shows as in the others, but no impulse came in

their case to resuscitation.

It seems possible to trace this force to an origin at the south. For

beginning with the north sub-tropic zone the gradient on the left shows

less and less steep southward to the south sub-tropic zone. Such a

dying-down swell is what should be looked for in an impulse which had

travelled from the south northward, since the wave would affect the

more northern zones last, and less of a calm period would intervene

between the two impulses from opposite poles.

The cartouches, then, state that the canals began to develop after the

greatest melting of the polar cap had occurred; that this development

proceeded down the latitudes to the equator, and then not stopping

there advanced up the latitudes of the other hemisphere. In the next

place they show that in the arctic region the development was arrested

and devolution or decay set in as it began to get cold there, the most

northern canals being affected first. Finally, that a similar wave of

evolution had occurred from the opposite pole some time before and had

then passed away. And this evidence of the cartouches is direct, and

independent of any theory.

CHAPTER XXIV

CANAL DEVELOPMENT

_Individually Instanced_

As an interesting instance of the law of development we may take the

career of the Brontes during this same Martian year; the Brontes

witnessing individually to the same evolutionary process that the

canals collectively exhibit.

The Brontes is one of the most imposing canals upon the planet. It is

not so much its length which renders it a striking object, though this

length is enough to entitle it to consideration, being no less than

2440 miles. Its direction is what singles it out to notice, for it runs

almost north and south. For this reason it swings into a position to

hold the centre of the stage for a time with the precision of a

meridian, as the planet’s rotation turns its longitude into view. The

points which it connects help also to add to its distinction. For the

Sinus Titanum at its southern end and the Propontis at its northern are

both among the conspicuous points of the disk. The latter is but twelve

degrees farther east than the former, while it is sixty-six degrees

farther north. This long distance,—from nearly the line of the tropics

in the southern hemisphere to mid-temperate regions of the

northern,—the canal runs in an absolutely straight course.

Its north and south character commends it for any investigation of

canal development, since it runs in the general direction that

development takes. Its great latitudinal stretch further fits it for a

recorder of changes sweeping down the disk; so that both in direction

and length it stands well circumstanced for a measure of latitudinal

variations. The fact that it is usually a fairly conspicuous canal does

not detract from its virtue in this respect. It was first recognized at

Flagstaff in 1894. But once realized, so to speak, it was possible to

identify it with a canal seen by Schiaparelli and supposed by him to be

the Titan; indeed, it played hide and seek with that canal throughout

his drawings. In 1894 both it and the Titan were so well seen that its

separate existence was unmistakable, causing it to be both recognized

and named. It is, like the Titan, one of the sheaf of canals descending

the disk from the Sinus Titanum, and lies just to the east of the Titan

in the bunch. In 1896 it was also prominent; and at both these

oppositions most so from its southern end, its northern one being more

or less indefinite, especially in 1894.

In 1901 it was not the same. Instead of being the conspicuous canal it

had been in earlier years, it was now so faint as with difficulty to be

made out. It remained so to the close of observations. It was now under

suspicion. Its behavior in 1896-1897 had led to the supposition that

not only were seasonal changes taking place in it, but that those

changes were such as to point to a law in the case with which its

conduct in 1901 fayed in. The suspicion did not, however, become a

certainty till the opposition of 1903. The length of time during which

the disk was then kept under scrutiny resulted in the method of its

metamorphosis being discovered.

[Illustration: I. February 25.]

At the very start of observations its longitude chanced to be nearly

central and it was made out; but so far off was the planet that only

its northern part could be detected, because, as afterward appeared,

this part was the stronger, the canal being decidedly inconspicuous,

whereas other canals, the northern and even the Pallene and the Dis,

were strongly marked. At the next presentation the planet was nearer,

and details previously hidden for the distance now came out. Among them

was the Brontes, which, showing better than in January, could be traced

all the way to the Sinus Titanum. A drawing (I) made on February 25 and

reproduced in the text shows its appearance at the time. Its emergence

under neared conditions only served to accentuate its relative

inconspicuousness, for it showed now notably inferior to the northern

canals, and this not only in the matter of general visibility, but in

the character it displayed. It was a line of hazy definition,

contrasting thus with the sharp dark forms of its northern neighbors.

[Illustration: II. March 30.]

[Illustration: III. April 3.]

As the planet steadily approached the earth, and the canals to the

north became better and better seen, the Brontes instead of sharing in

the general improvement did exactly the opposite. It grew less visible

when it should have grown more so, if distance had been the cause of

its appearance. It was now only to be seen at the north, even when it

was seen at all; a state of things exemplified in Drawings II and III.

[Illustration: IV. May 4.]

As the planet now went away and detail should have dimmed, the Brontes

proceeded to do the opposite. One had almost said it was actuated by a

spirit of contrariety. For now when it had reason to grow faint it grew

in conspicuousness; just as, before, when it should have become

evident, it had declined. Distinctly farther off and smaller as the

planet was at the next presentation, the Brontes had clearly developed

both in tone and in the amount of it visible. This was in May (Drawings

IV and V). In June bad seeing prevented good observations, but in July,

Drawing VI, when the region again came round, the Brontes, in spite of

the then greatly increased distance, asserted itself so strongly that

even in not very good seeing its presence could not be passed by.

[Illustration: V. May 7.]

This contrariety of behavior had about it one very telling feature.

That the canal waxed or waned in exact opposition to distance and even

toward the last to seeing too, showed conclusively that neither

distance nor definition could in any way be held responsible for its

metamorphoses. A very fortunate circumstance, this of the observations,

for it directly eliminated size of disk, phase, and seeing, for which

correction are none too easy to make, and which in the minds of the

sceptical could always remain as unexplained possibilities of error.

[Illustration: VI. July 18.]

The mean-canal cartouches show synthetically, and all the more

conclusively for being composite, the laws of the flux of the canals.

Something more of vividness, however, is imparted by the actual look of

one of the constituents during the process. It is the difference

between seeing a composite picture made from a given group of men and

the gazing on the actual features of any one of them. So much is gained

by the drawings across the page of the Brontes at different stages of

its evolution during the period here concerned. But in another way,

too, the one canal may be made to yield a more lifelike representation

of the process than a number taken together are capable of affording.

In the mean-canal cartouches each canal is treated as an entity; but it

is possible to consider a canal by parts, and by so doing to see it in

action, as it were. It occurred to me to treat the Brontes in this way.

For this purpose I divided the canal into sections, five of them in

all, between the point where it left the Propontis, at a spot called

the Propropontis, to where it ended in the Sinus Titanum. The first,

the most northern, extended as far as Semnon Lucus, the southernmost

outpost of the Propontis congeries of spots. The second continued on

from these to Eleon, the junction where the Erebus crossed. The third

thence to Utopia, where the canal met the Orcus; the fourth to an

arbitrary point in latitude 8° south, and the fifth and last to the

Sinus Titanum. The lengths of these sections were respectively: 12°,

16°, 15°, 12°, and 13°. Each of the sections was then treated as if it

were a separate canal and its cartouche found. To the cartouches’

determination there were available drawings:

January 21-25 12 drawings.

February 23-March 2 15 drawings.

March 28-April 5 14 drawings.

April 26-May 8 27 drawings.

June 3-16 6 drawings.

July 11-21 16 drawings.

-------------------

90 drawings in all.

The cartouches are given in the plate opposite, which is constructed

precisely like the one for the mean canal cartouches presented on page

298. The mid-latitude of the section and its mid-longitude are given in

the margin with its description.

[Illustration: BRONTES

Showing Successive Development South

_January to July, 1903_

P.L.]

Examining them now we note a family resemblance between the successive

cartouches. All sink slowly on the left to rise sharply from their

lowest point to the right. Such resemblance betokens the action of one

and the same cause.

Next, although the curves are resemblant, each has been, as it were,

sheered to the right as one reads down; that is, the action took place

later and later as the latitude was north.

Lastly, the dying out of a previous impulse can be traced in the

cartouches, which shows that the canals were quickened six months

previously from the south polar cap, as they were now being quickened

from the north polar one.

CHAPTER XXV

HIBERNATION OF THE CANALS

Connected with the conduct of the canals is a phenomenon, examples of

which were early noted in a general way by Schiaparelli and later, but

of which the full import and exhibition only came to light during the

opposition of 1903 by a very striking metamorphosis: what may be called

the hibernation of a canal for a longer or shorter term of years. What

observation discloses is certainly curious. For several successive

oppositions a canal will be seen in a definite locality, as regular in

seasonal recurrence as it is permanent in place, a well-recognized

feature of the disk. Then to one’s surprise, with the next return of

the planet, it will fail to appear, and will proceed to remain

obliterate without assignable cause for many Martian years, until as

unexpectedly it will be found what and where it was before. Neither to

deposition of hoar-frost, such as frequently whitens whole regions of

Mars, nor to other circumstances can be attributed its disappearance.

Without apparent reason it simply ceases to be and then as simply comes

back again.

Such bopeep behavior is quite beyond and apart from the seasonal change

in visibility, to which all the canals are by their nature subject. For

being creatures of the semi-annual unlocking of the water congealed

about the polar caps, they quicken into growth and visibility, each in

its season, and as regularly die out again. Different, however, is the

phenomenon to which I now refer. In it not a seasonal but a secular

change is concerned. The season proper to the canal’s increase will

recur in due course, and the canals round about it will start to life,

yet the canal remains unquickened. Nothing responds where in years the

response was immediate and invariable. The canal lies dormant spite of

seasonal solicitation to stir.

Such curious hibernation was early hinted to the keenness of

Schiaparelli, and most incomprehensible as well as difficult of

verification at that stage the phenomenon was. That the absence was a

fact, however, he assured himself, although he was not able to prove an

alibi. But at the last opposition an event of the sort occurred which,

from the length of time the planet was kept under observation, combined

with continued suitableness of the seeing, unmasked the process. In the

light of what then happened, taken in connection with the side-lights

thrown upon it by the canal’s past and by the knowledge we have

meanwhile gained of the planet’s physical condition, the riddle of the

phenomenon may in part at least be read, and most interesting and

instructive the reading proves to be.

Among the initial canals detected by Schiaparelli, in 1877, was a

tricrural set of lines recalling the heraldic design of three flexed

legs joined equiangularly above the knees. It lay to the east of the

Syrtis Major, and he called its three members the Thoth, the Triton,

and the Nepenthes. Starting from the head of his gulf of Alcyonius, at

a point now known to be occupied by the oasis called Aquae Calidae, the

Thoth started south inclining westward as it went, till in longitude

267° and latitude 15° north, it met the Triton, which had come from the

Syrtis Minor with similar westward inclination. To the same point in

the same manner came the Nepenthes. Part way along the course of the

latter was to be seen a small dark spot, the Lucus Moeris, which he

estimated at four degrees in diameter. Some of the markings were easier

than others, the easiest of all being the Lucus Tritonis, a largish

dark spot at the common intersection of all three canals; but that none

of the markings were remarkably difficult is sufficiently shown by

their detection at this early stage of Schiaparelli’s observations. It

is worth noting also that he discovered the southern ones first; the

Thoth not being seen till March, 1878. As his then recognition of these

canals witnesses, they must have been among the most evident on the

disk. And the point is emphasized by the fact that he failed at this

opposition to detect the Phison and the Euphrates as separate markings.

Much the same the three canals appeared to him at the next opposition

of 1879, the Thoth being seen at its several presentations from October

5, 1879, to January 11, 1880.

At the next opposition a noteworthy alteration occurred, the full

significance of which escaped recognition. Schiaparelli saw, at the

place where the Thoth had been, two lines which he took for a

gemination of that canal, one of which followed the course of the old

Thoth, while the other went straight from the Sinus Alcyonius to the

Little Syrtis, or, more precisely, to the junction of the Triton and

the Lethes. It was not the Thoth, however, but something unsuspected,

of more importance.

In 1884 the Thoth showed really double, the western line being much the

stronger, “una delle piu grosse linee que si vedessero sul disco.” That

neither branch went farther than the meeting-place with the Nepenthes

argues that it was indeed the Thoth that was seen. Schiaparelli himself

had no doubt on the subject, although he drew the double canal he saw

due north and south from the tip of the Sinus Alcyonius to the

junction, but nevertheless along the 263° meridian.

In 1886 and 1888 the system was in all essentials, what it had been in

1877 and 1879, except that the Thoth and Nepenthes were double and were

more minutely seen.

Here, then, was a system of canals and spots which for six Martian

years had been a persistent and substantially invariable feature of the

Martian surface. Any changes in it had been of a secondary order of

importance, while its general visibility was of the first. It is

possible, then, to judge of my perplexity when in beginning my

observations in 1894 no sign of the system could I detect. Of neither

the Thoth, the Triton, the Nepenthes, nor the Lucus Moeris was there

trace. And yet, from the other canals visible, it was evident that the

disk was quite as well seen as it had been by Schiaparelli. Not only

were practically all his canals there, but many much smaller ones were

to be made out. And the same was true of the spots, a host of such not

figured by him appearing here and there over the planet’s surface.

Nor was this all. Instead of the Thoth, another canal showed straight

down the disk from the Syrtis Minor to the Aquae Calidae. This canal

was as unmistakable as the Thoth had been before to Schiaparelli. It

was among the first to be detected, and continued no less conspicuous

to the end, the dates at which it was seen being July 10, August 14,

and October 21. I called it the Amenthes, identifying it with the canal

so named in Schiaparelli’s chart published in _Himmel und Erde_, of the

_ensemble_ of his observations from 1877 to 1888. But in his Memoirs he

never called it so, seeing it, indeed, only in 1881-1882, and deeming

it then the Thoth. Nevertheless, in 1894, it was the conspicuous canal

of the region, and, what is more, had come, as it proved, to stay.

The invisibility of the Thoth continued for me the same during the

succeeding oppositions of 1896-1897 and 1901. At the former opposition

I drew it in 1896 on July 28, August 26, September 2, October 5-9,

seeing it single; and in 1897 on January 12-19, February 21, and March

1. It was single but with suspicions of doubling in January, and was

indubitably double in February. As for the Thoth, I had come to

consider it and the Amenthes one, attributing their diversity of

depiction to errors in drawing. For while the Thoth remained

obstinately invisible, the Amenthes presented itself as substitute so

insistently as to make one of the most obvious canals upon the disk.

One exception only was there to this state of things. On June 16, 1901,

my notes contain this adumbration of a something else: “Amenthes

sometimes appeared with a turn to it two-thirds way up; two canals

concave to the Syrtis Major.”

[Illustration: Amenthes alone in February.]

So matters opened at the opposition of 1903. With the advent of the

planet and the presentation in due course of Libya in February, the

Amenthes duly appeared, much as it had showed at the opposition before,

only less salient. It was a confused and seemingly narrower double.

Suspected on the 16th of that month, it was definitely seen from the

18th to the 23d. Of the Thoth no mention is made either in the notes or

in the drawings. When the region came round again, in March, the

Amenthes was still there, showing more feebly, however, than it had in

February, in spite of better seeing and the fact that the planet had

considerably neared. Clearly the canal was fading out; a fact further

witnessed to by the following note made on March 25: “Throughout this

opposition thus far the dark triangle tipped by Aquae Calidae has been

sharply divided in intensity from the Amenthes, which is very narrow

and exceedingly faint.” Still was there no trace of the Thoth.

[Illustration: Amenthes feebler and still alone in March.]

With the April presentation entered a new order of things. When the

region first became visible, on the 16th, the Amenthes could still be

seen and alone; but on the 19th, as the relative falling back of the

Martian longitudes swung the region nearer the centre of the disk, the

Thoth appeared alongside of it. On the 20th the Thoth showed alone.

Unmistakable it was and just as Schiaparelli had drawn it, accompanied

by the Triton and the curved Nepenthes. The thing was a revelation.

What before I had seen only in the spirit of another’s drawings stood

there patent to me in the body of my own; while the Amenthes, to which

I had so long been accustomed, had vanished into thin air. Only a trace

of it was now and then to be made out. So startlingly strange was the

metamorphosis that I could not at first trust my eyes, and questioned

the broken line, which had replaced the straight, for some ocular

deception. But nothing I could do would rectify it. The Amenthes was

gone and the Thoth stood in its stead.

[Illustration: Appearance of Thoth with Triton and curved Nepenthes.

Amenthes vanished. April 20.]

At the next presentation, May 26 to June 8, the phenomena were

repeated, and with increasing clarity. And then of a sudden, on May 29,

I saw the long-given-up Lucus Moeris. There it was indubitably. And its

definiteness was the most astonishing part of the affair. It was no

question of difficult detection. Indeed, I had not been on the lookout

for it, having searched the region too often fruitlessly before to have

left incentive to search again. And so, when I was not searching, the

thing of its own accord stepped forth to sight. It was a small round

dot, like to any other oasis, and showed, as it were, a black pearl

pendent by the Nepenthes from the Syrtis’s ear. For the Libyan bay made

a dark projection of the sort high up on the Syrtis’s eastern side,

from which the Nepenthes, precisely as Schiaparelli had drawn it,

curved down to the point where the Thoth and Triton met. All three

canals were geminated, the gemination being about three degrees wide.

[Illustration: Advent of the Lucus Moeris. May 29.]

And now occurred the last act in the drama. In July the Amenthes

reappeared, showing alongside of the Thoth-Nepenthes, and thus removing

any possible doubt as to their separate identity. It had, indeed,

become the stronger of the two, having gained in strength in the

interval between June and July and the Thoth-Nepenthes having lost. The

lines were in process of relapsing into the _status quo ante_. Had

these three presentations not been watched, the brief apparition of the

Thoth-Nepenthes had been missed and with it the revealing of its

curious character, and of certain deductions thereupon.

[Illustration: Amenthes with Thoth-Nepenthes. July.]

First among these is a truth of which I have long been convinced; to

wit, that when a seeming discordance arises between the portrayals of a

canal, it is commonly not a case of mistake nor of change, but one of

separate identity. The canal has not shifted its place, nor has an

error been committed; the fact is that one canal has been observed at

one time, another at another.

So it was here, and thus were the old and the new observations

reconciled. There had been no mistake in either. Two separate canals

accounted for the discrepancy, and only an unfounded distrust of the

accuracy possible in such observations was to blame for any failure to

recognize the fact.

Now, scrutiny of the notes upon the appearance of the two canals,

together with their labeling by the seasonal longitudes of the planet

at the dates they were made, discloses a curious relation between the

two. The seasonal longitudes are important, as they date the phenomena

according to the Martian calendar. Ordered thus, the successive aspects

reveal first a seasonal change in each canal and then over and above

this a secular one. And this secular change was such as to cause the

two canals to alternate in visibility. When the one was present the

other was not, and _vice versa_.

[Illustration:

CARTOUCHES

OR

CURVES OF VISIBILITY

OF

AMENTHES, THOTH AND THEIR COMBINATION.]

We shall see this more clearly and at the same time bring out a curious

relation between the two systems, the broken bow of the

Thoth-Nepenthes-Triton and the straight arrow of the Amenthes, while

looking at the cartouches of the Thoth, the Amenthes, and a combination

of both given in the plate on previous page.

The antithetical character of the two canals is apparent. But what is

further interesting, the combination cartouche of both bears a singular

resemblance to that of the mean canal of the north tropic zone, the

zone to which both canals belong. Here, then, is a combination which is

perfectly regular while each of its constituents is anomalous.

And now we come to something as important: at the opposition of 1905

the curious alternation metamorphosis was enacted anew. The Amenthes

appeared, disappeared to be replaced by the Thoth, and then reappeared

again beside the other. This corroboration of behavior showed the

previous observations to have been due to no mistake, and only served

to deepen the interest in this last and more singular phase of canal

conduct.

CHAPTER XXVI

ARCTIC CANALS AND POLAR RIFTS

Last in time but not least in importance of the details of canal

development to be detected is one that connects these strange features

directly with the melting of the polar caps. The cartouches showed that

such connection was to be inferred; the facts now to be recorded depict

it by an identity of place between certain phenomena of the two

subjects following one another in order of time.

On January 8, 1897, while scanning the planet, I was suddenly ware of a

rift in the north polar cap. It ran a little to the west of south from

where it started in at the cap’s edge and went clean through to the

limb, the pole being then slightly tilted away from us. At the time it

seemed to be the first rift ever seen in that cap; but on opening a

little later Schiaparelli’s _Memoria Quarta_, which had just arrived,

the first thing my eye fell on was a drawing of a rift in the north

polar cap observed by him when the planet had held the like attitude

toward the Earth thirteen years before. Reference to its longitude

showed it to be the identical rift, seen again after all these years

and the only one so far seen in the northern cap.

At the next opposition more rifts were detected, one in especial on

December 27, running from Arethusa Lucus, then upon the edge of the

cap, athwart the snow in a northwesterly direction.

In the forepart of the opposition of 1901, which in its Martian season

corresponded to that in 1897, when the rift had been observed, many

rifts were detected in the cap, and among them one traversing the cap

north-northeasterly in longitude 136°.

So far the season when the cap had been observed was that when the

rifts were in process of forming. The ground they and the snow-cap

covered had not yet at any opposition been uncovered.

It was only when my observations began in the latter half of the

opposition of 1901 that, the season on Mars having so far advanced, all

snow in those latitudes had melted. Then appeared, however, the canal

Hippalus, an arctic canal of some importance, lying on that part of the

planet previously occupied by the polar cap. When later studying the

observations on the rifts I remembered this canal, and turning to the

drawing made some months before to compare the two critically,

discovered that the canal occupied the precise position held earlier by

the rift. One had said the rift had never vanished, but that the white

surrounding it had simply turned to ochre. Here, then, was a striking

coincidence of place, too exact to be the result of chance.

Impressed by the identity, I examined all the other rifts seen early in

1901, comparing them with the arctic canals seen later, to the finding

of no less than five cases of the same coinciding positions.

The importance of the identification here made of an arctic canal with

a previous rift in the polar cap has led me to make a list of the

canals thus identified at this opposition.

==========+===========================+=============================

| VISIBLE AS A RIFT | VISIBLE AS A CANAL

----------+---------------------------+-----------------------------

Hypanis | January 1 and February 4 | April 18 (?), May 20, 22,

| | 27, June 4, 5, 6, 7, 8, 25

Hippalus | January 19 and February 4 | April 18, May 27

Rhombites | February 4 | May 27

Python | February 20 | March 31

Zygatis | January 18, 19 | May 7, June 3 to 8

==========+===========================+=============================

If it be asked why these canals do not appear recorded at the March

presentation as either the one phenomenon or the other, the answer is

twofold. First, because they showed as shadings lost amidst a shaded

mass; and, secondly, the observations at several oppositions indicate a

great amount of haze over the region at that season of the Martian year.

We may now go back to the very first rift, that of 1897. The Martian

season grew later with each succeeding opposition, and it so chanced,

abetted by this fact, that the delaying snow was never seen covering

that part of the planet again and so, of course, not the rift. The

Martian summer in those high latitudes came on, and with it brought the

great arctic canal, the Jaxartes, into conspicuousness. The canal in

consequence had been observed for some time before it proclaimed itself

the apotheosis of a rift and that of the first and most important rift

of all. Comparison of position, however, entirely confirmed the

conjecture and added another and the most striking of all to the list.

These six canals, on the whole the largest which run into the northern

cap, have thus a dual character. Starting originally as rifts, they

later come out unmistakably as canals. So that we may say in general

that the two phenomena are different seasonal states of the same thing.

This instantly explains the rifts, the origin of which we found of so

difficult, not to say impossible, interpretation before in these pages,

and incidentally it confirms what we deduced on other grounds as the

character of the canals; to wit, strips of vegetation. For if the cap

covered desert and fertility alike, it is precisely over the latter

that it would first melt.

Vegetation has the property of melting snow. The metabolism of the

plant, like that of the animal, though in a less degree, generates

caloric. A living animal is warm, even the so-called cold-blooded ones,

in some sort, and a growing plant is too. The chemic processes

concerned give off heat, though in such small quantities that we are

often not aware of it. While the plant lies dormant it stays cold, but

the moment its sap begins to run under the rays of the spring sun it

rises in temperature above its winter surroundings. All it needs to

this awakening is sun and water, and both it gets in its place in the

polar cap after the passing of the vernal equinox. The time, therefore,

is suitable, for it is not till after that equinox is passed that any

of the above phenomena occur. In consequence the snow about it melts

and the plants themselves show as dark rifts splitting the cap.

This quite unexpected identity of two seemingly diverse phenomena, and

the unsolicited support its only explanation lends to the general

theory, is an instance of what is constantly occurring as observation

of the planet is pushed farther and farther. Facts every little while

arise which prove to fit into place in the scheme when neither the

facts nor their fitness could have been foreseen.

CHAPTER XXVII

OASES: KINEMATIC

Subject to change also are the oases; and in the same manner apparently

as the canals. They grow less evident at a like season of the Martian

year. They do this seemingly by decreasing in size. Whereas in the full

expanse of their maturity they show as round spots of appreciable

diameter, as the season wanes they contract to the smallest discernible

of dots. All but the kernel, as it were, fades out, and even this may

disappear from sight. The Phœnix Lake in its summer time is a very dark

circular spot, small indeed yet of definite extension; in its winter it

shrinks to a pin point, and is often not visible at all. Sometimes the

husk apparently persists, a ghostlike reminiscence of what it was, with

the kernel showing dark-pointed in its centre. Thus the Lucus Lunae

appeared at the opposition of 1905. A faint wash betokened the presence

of the Lucus, through which now and again a black pin-point pierced.

In this visible decrease of size we get a revelation as to what takes

place impossible in the case of the canals, the tenuous character of

which precludes more than inference as to the process.

Like the canals, latitude, together with the suitable season of the

planet’s year, are the determining factors in their development. In

what corresponded to our July of the northern hemisphere the oases in

the sub-arctic and north temperate zones were conspicuous; black spots

that showed in profusion along the parallels of 40°, 50°, and 60°

north. At the same time the equatorial ones, those along the

Eumenides-Orcus, which had been most evident in 1894, hardly came out.

It had been their time then as it was that of the others now. The law

of development is not so simple as on the earth, depending, like that

of the canals, not only upon the return of the sun, but upon the advent

of the water let loose from about the polar caps. Thus the equatorial

oases are subject to two seasonal quickenings, one from the north, the

other from the south.

In regard to their method of evolution or devolution a most curious

observation happened to me in 1903. Usually the oases are of solid tone

throughout; equally sombre from centre to circumference. But in this

case such uniform complexion found exception. On March 1, 1903, the

Ascraeus Lucus came out strangely differentiated, a dark rim inclosing

a less dark kernel. The sight was odd enough to command comment in the

shape of a sketch which accompanied the note, and the further remark

that other spots had similarly that year affected the like look. That

the effect was optical did not seem to me the case. Other spots at

other times showed nothing of the sort. If it was due to objective

cause it gathers circumstance from what was then the Martian time of

year. For the season was such that the spot should then have been in

process of waning; and the effect would indicate that in so doing the

tone of the centre went first, that of the circumference fading last.

This would be in accordance with a growth proceeding outward and a

decay that followed in its steps.

When to this we add the look of the oases at the antithetic

season,—often a faint shading only, with or without a darker pin-point

at its core,—we are led to the belief that the area of the oasis is

unchangeable and that its growth means a deepening of tint.

So far, then, as it is possible to particularize them, the oases

develop from a small nucleus, perhaps twenty miles in diameter, perhaps

less, and from this spread radially till they attain a width of

seventy-five or one hundred miles. If the oasis be associated with a

double canal, this maximum width exactly fits the space between the

twin lines. Even when no double enters the oasis, the size is about the

same. This size attained, they hold it for some months. Then they

proceed to fade out to their initial nucleus, and after a sufficient

rest the process starts over again.