by Various
"The proof of their existence, however, no longer rests only on the corroborative evidence of other observers, for, after years of experiment, Professor Lowell and his staff have succeeded in taking direct photographs of Mars, which show several of the disputed lines. One would have thought that would settle the question, but, although some of the more reasonable of the objectors have been convinced by the evidence of the photographs, many others still maintain their attitude of scepticism, especially those who have not themselves seen the photographs. They declare it to be quite impossible for any such photographs to be taken, because our atmosphere would prevent any photographic definition of fine detail on such small pictures; yet about ten thousand of these tiny photographs were taken during the near approach of Mars in 1907.
"As I possess a number of these photographs I can testify that they do show some of the lines, and persons who disbelieved have expressed surprise at their excellence. Success was only obtained by means of specially sensitised plates, for the ordinary photographic rays and ordinary plates were found useless, whilst the process of photographing so small and distant a planet is surrounded with difficulties.
"Even when attached to a telescope giving an equivalent focal length of nearly 150 feet, the camera only gives a very tiny image of the planet. The lighting of the small image is faint, but if additional power were used on the telescope to obtain a larger image, then its light must be still fainter, and thus a longer exposure would be required to obtain a picture on the plate. As Mars moves in its orbit and rotates on its axis, and our atmosphere is subject to continual movement and disturbance, any long exposure would result in a blurred picture, which would show no fine detail. So, as a short exposure is essential, only a small picture can be taken. Nothing is gained by any subsequent great enlargement of the picture, because the grain of the film of a quick plate is coarse; and, if enlarged, this also blurs out the detail.
"Having regard to all the difficulties which had to be surmounted, it was a great and undoubted triumph to secure detail on such tiny photographs of this distant world. As time goes on improvements will probably be effected and still better pictures secured; but enough has now been accomplished to prove that the lines cannot be illusions, but really exist upon the planet. If the eye can be deceived in this respect, the camera cannot.
"When Professor Lowell first took up the work of Martian observation only 113 lines had been discovered by Schiaparelli, but the number has gradually been added to from time to time, as the result of the work done at Flagstaff Observatory and elsewhere, and has now reached a total of considerably more than 600, the lines forming a fine network extending all over the planet.
"Mr. Slipher, who accompanied Professor Todd's expedition to Alianza in Chili, at the opposition of 1907, together with the observers at Flagstaff, discovered no less than 85 new canals, including some doubles, nearly all being in the more southern portions of the southern hemisphere.
"In addition to the discovery of so many fine lines, we also owe to the acumen of Professor Lowell a reasonable explanation of what they really are. Schiaparelli termed them 'canali,' an Italian term for 'channels,' but, popularly, this soon became corrupted into the term 'canals,' and this has turned out to be a much more appropriate word than such corruptions usually are.
[Illustration: From a Globe made by M. Wicks Plate IX
MARS. MAP II
The Solis Lacus is seen as an oval patch near the top, and many long canals, some double, are shown. A very large proportion of the area on this map is desert land.]
CHAPTER XI
THE GREAT MARTIAN CONTROVERSY (continued)
"As the result of very long continued and systematic observation of the lines on Mars, together with carefully plotting them down on a globe, it was found that every line was continuous, uniform in width, and went straight from one definite point to another, not one breaking off in open space. Moreover, on being tested, nearly all were found to be arcs of great circles, and therefore the shortest possible lines which could connect any two points on a sphere. This fact strongly supports the idea that they are not natural but artificial formations. For a long time the lines were only seen on the red, or lighter, parts of the planet, but in 1892 an expedition was sent from Harvard Observatory to Arequipa, in Peru, for the purpose of observing the planet under very favourable conditions, and this resulted in important discoveries. Professor W.H. Pickering, who accompanied the expedition, was fortunate enough to observe that the canal lines extended over the dark or blue-green portions of the disc; and later observations have proved that this is the case all over the planet, and the lines are visible from pole to pole.
"These observations also led Professor Pickering to the important conclusion that all the dark areas were covered with vegetation, and that the bright or red areas were deserts, the colour of the latter being exactly that of our deserts when viewed from a great distance. Herschel's idea had been that the red areas were land covered with vegetation of a red colour, and that the dark areas were seas.
"It was, however, now quite clear that permanent lines in such numbers and length could not exist in seas; and other observations have demonstrated that, instead of appearing smooth and uniform as water would, these areas are full of detail and variations, and that they pass through all the changes of colour, according to seasons, that land covered with vegetation does upon our earth. In the winter time, when the land is fallow, it appears brown or chocolate colour; in the spring, the time of early vegetation, it becomes a pale blue-green tint; as the season advances the blue-green becomes darker; whilst in the autumn it tends to a light brown, and at length changes into chocolate colour in the winter. This has been carefully noted time after time when the planet has been in a position to be observed; and the same sequence of change--which can only be associated with vegetation--has always occurred.
"It may, therefore, now be accepted as a proved fact that the dark areas are land upon which vegetation grows, ripens, and dies away according to the seasons of the Martian year.
"Professor Pickering also made another discovery, viz. a large number of isolated, round, darkish spots, most of which occurred where canal lines joined or crossed each other. Some of these had been seen much earlier by other observers, but Professor Pickering was the first to see them in large numbers and call attention to them. He termed them 'lakes,' but later discoveries from continued observation showed that they were not water, and they were then given the name of 'oases.' Some are seventy or eighty miles in diameter, and nearly two hundred are now marked on the maps. They mostly occur in certain definite positions--in the point where single canals join or cross each other, or, in the case of double canals, between the two lines. It has been noted that they undergo the same seasonal changes as the dark areas do, but only as regards the outer portion of the circle, which gradually fades away in the latter part of the Martian year; whilst the central portion becomes fainter but does not disappear.
"Of course it was at once declared that these oases were illusions which would naturally be seen where two lines crossed each other and were viewed from a great distance. But they only occur in some cases at such crossings, and there are many junctions without any oases. Moreover, they are also seen between the double canals where there are no junctions nor anything which could give rise to illusion.
"At Flagstaff Observatory it was also noted that the canal lines themselves underwent seasonal changes. Those viewed during the winter season were always so faint as to be scarcely discernible, but at the period when vegetation would naturally begin to grow they became more easily visible, and still more distinct as the season advanced.
"Then Professor Lowell announced his great conception, which has given rise to so much controversy, and has also been much misunderstood and misrepresented.
"Briefly, his conclusions were as follows:--'Science teaches that a small planet will become cool and develop life much sooner than a large one. Similarly a small iron casting will become cool in a few da
ys, whilst a large one will be many weeks or even months in cooling. A small planet will also develop more rapidly, and reach its final stage when it will be incapable of supporting life, very long before a larger planet like our earth will have reached that stage. Applying this to Mars, a much smaller planet than our earth, it is scientifically reasoned that Mars has passed through nearly all its stages and is approaching its last. It has lost much of its atmosphere, all its large bodies of water, such as oceans or seas, and, as regards the land, that has become levelled by erosion, and about five-eighths of the whole area has become desert.
"'Science also shows that in such circumstances rain would cease to fall over the larger part of the planet, but the water vapour in the air would be carried by natural circulatory currents of air to the polar regions, and there deposited in the form of snow or hoarfrost, thus forming a large snow-cap at the north pole in one season of the year, and a still larger snow-cap at the south pole in the opposite portion of the year.
"'These snow-caps would begin to melt in the spring as soon as the tilt of the planet brought the pole to the position where the sun would take effect, and would continue during the early summer. As there is no permanent glaciation on a planet which has lost its water, the snow-cap would melt to a very large extent, and the resultant water must go somewhere.
"'The inhabitants of the planet could not exist without water, and their land would become entirely desert unless supplied with moisture. It will, therefore, be seen that the only thing possible, as a means of self-preservation, would be for them to make channels to carry the water in the most economical way from the poles to the parts where it was needed. Unless they found a means of doing this death stared them in the face. What greater incentive could there be!'
"This is what Professor Lowell is convinced has actually been accomplished upon Mars, with the result that there is a network of canals all over the planet by which water is conveyed from each pole and carried across from one hemisphere into the other. The lines seen show where the canals are, but not the canals themselves, because they are too narrow to be seen. The lines really are broad bands of vegetation irrigated by the canals which run through them, hence the seasonal changes which have been noted in their colour.
"All this seems very reasonable, deduced as it is from scientific fact and from the many different things which have actually been seen and confirmed by many thousands of observations, but it has met with the most bitter opposition on the part of many astronomers, both professional and amateur. Theory after theory has been brought forward with the object of disproving the existence of the canal lines; some of these, such as eye-strain, diplopia, bad focussing, illusion, and imagination, have already been mentioned.
"Proofs of the reality of the lines having become too strong for most of the objectors, they then turned their endeavours to the overthrowing of the theory that the lines were canals, suggesting that they were all of natural origin.
"Amongst these suggestions it was stated they were edges of shadings, natural growths of long lines of trees and vegetation, cracks in the surface of the planet or foldings caused by contraction, trap-dykes, &c., but not one of these suggestions will bear investigation. I have already pointed out the impossibility of shadings having straight edges for thousands of miles in so many hundreds of cases. It is equally impossible to imagine natural growths of trees and vegetation in bands of uniform width and thousands of miles long, and nearly all forming arcs of great circles.
"They cannot be cracks, for they are of uniform width throughout their length, and always run direct from one definite point to another, no matter how distant apart they may be.
"Cracks, such as we see on the moon, though sometimes straight, are usually wide near the centre of disturbance which caused them, and narrow off to a fine point, and often end anywhere out in open space; moreover, they are usually very irregular in width, and take a zig-zag course instead of a straight one. This, as I have said, is not the case with a single canal line on Mars. If they were cracks, some at least would be irregular and end in open space. The same remarks apply in the case of foldings or ridges.
"The oases, once declared to be illusions, were then said to be large openings in the soil at the junctions of the cracks; or they might be craters, and so on. But this does not account for the appearance of the oases between twin canals, or the systematic manner in which the canals effect a junction with the oases. Again, therefore, the theory fails to fit the known circumstances of the case.
"Dr. A.R. Wallace rather favours the idea of natural cracks or faults in the surface of the planet; and suggests that the outer crust of Mars may be a crystalline or similar formation which would lend itself to the production of numerous cracks in the surface. He points to a few cracks and faults in the earth's surface, all of small size, as confirming this idea; but the cases he adduces only seem to prove that there is on our earth absolutely no natural formation which can in any way properly be compared with the lines seen on Mars. Moreover, there seems to me no ground whatever, beyond the needs of the theory, for supposing that the crust of Mars is of a crystalline nature, or such as would predispose to the formation of cracks. On the contrary, all the evidence is against it--the existence of vegetation in some parts, the general appearance of the red portion, and the large clouds of sand which have been observed, all being indicative of a sandy formation, in the red portion at least.
"The theory also fails to take into consideration the most important point of all, viz. that every canal runs direct from one definite point to another, perhaps over two thousand miles distant. In very many cases numerous lines connect with one small area, or even with one point. The Lucus Ascræus has no less than seventeen of these canals connecting with it, and appears to be a kind of Martian Clapham Junction.
"The deserts on Mars serve the same purpose as our seas, as lines of communication may be established anywhere across them. A map of Mars, showing the canals converging towards some one part, bears a great resemblance to our maps showing the courses taken by vessels from different parts all converging upon one seaport.
"Much has also been said about the widths of the canals as rendering them impossible of construction, so let us consider how wide they are.
"The lines seen vary from two or three miles up to nearly thirty miles in width; but there are only one or two of the latter, and the majority are five to ten miles wide. Notwithstanding Professor Lowell's repeated statements that they represent bands of vegetation, these widths are often referred to as the widths of his canals. I have frequently seen them described as 'fifty miles,' a 'hundred miles,' and even as 'hundreds of miles' wide. These exaggerations usually appear in newspapers and journals, and evidently arise from insufficient knowledge on the part of the writers.
"Owing to the small gravitation upon Mars, the work of digging canals would be extremely easy upon that planet (even assuming the Martians to be without machinery) as compared with the same work on our earth; but there is neither necessity nor reason for the construction of such enormously wide canals as those mentioned. Moreover, it seems to me that very wide canals would defeat the object for which they were constructed; and Professor Lowell does not regard the widest lines as being canals. They may be remains of natural channels or arms of the seas, as they do not run so straight as the canal lines proper.
"Our people," I remarked, "have argued both against the possibility of constructing such canals and of forcing water along them, because, as they say, none of our engineers would be able to accomplish such work. I certainly have more confidence in the skill and capabilities of our engineers, and doubt not that if they were required to solve a similar problem they would overcome all difficulties and carry out the work successfully."
"I'm with you there, mon!" exclaimed M'Allister.
"I may remind you," I proceeded, "that when steam navigation was first mooted, it was confidently asserted that no steamship would ever succeed in crossing the Atlantic Ocean, and I can remember when it was
learnedly demonstrated that it would be quite impossible to construct a canal across the Isthmus of Suez! How small the prophets must have felt when the work was accomplished!
"I am afraid it is usual to take a very limited view of all such matters, and we judge of them entirely from what we know ourselves, never looking ahead, as it is considered unscientific to go beyond our own knowledge. Because something may be quite impossible to us, it does not follow that it is impossible to more advanced people.
"Think how many great scientific facts which are quite commonplace at the present time were unknown and undreamed of even so recently as our grandfathers' time! Who then can forecast what may be possible five hundred years, or even a century hence; and who will be bold enough to fix a limit to the possibilities of science! I freely admit I am an optimist in these matters."
"I think, Professor," said John, "that your view is really the more scientific of the two. While it may not be possible accurately to forecast all the facts, intelligent anticipations may logically be formed from a survey of our own past history."
Proceeding, I then remarked, that "Another discovery made at Flagstaff Observatory was that at the ends of certain canals, where they joined the dark areas, were small V-shaped dark markings which Professor Lowell has termed carets. From their occurrence in these positions only, and from his observations of the peculiar and extremely systematic manner in which the canals, especially the double ones, run into the carets, he has concluded that they must serve some special and important purpose.