"'Science also shows that in such circ.u.mstances 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 h.o.a.rfrost, 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 ca.n.a.ls 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 ca.n.a.ls are, but not the ca.n.a.ls themselves, because they are too narrow to be seen. The lines really are broad bands of vegetation irrigated by the ca.n.a.ls 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 ca.n.a.l 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 ca.n.a.ls, 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-d.y.k.es, &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 s.p.a.ce; 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 ca.n.a.l line on Mars. If they were cracks, some at least would be irregular and end in open s.p.a.ce. 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 ca.n.a.ls, or the systematic manner in which the ca.n.a.ls effect a junction with the oases. Again, therefore, the theory fails to fit the known circ.u.mstances 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 ca.n.a.l 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 Ascraeus has no less than seventeen of these ca.n.a.ls 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 ca.n.a.ls 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 ca.n.a.ls 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 ca.n.a.ls. 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 ca.n.a.ls would be extremely easy upon that planet (even a.s.suming 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 ca.n.a.ls as those mentioned. Moreover, it seems to me that very wide ca.n.a.ls would defeat the object for which they were constructed; and Professor Lowell does not regard the widest lines as being ca.n.a.ls. They may be remains of natural channels or arms of the seas, as they do not run so straight as the ca.n.a.l lines proper.

"Our people," I remarked, "have argued both against the possibility of constructing such ca.n.a.ls 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 a.s.serted 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 ca.n.a.l 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 antic.i.p.ations 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 ca.n.a.ls, 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 ca.n.a.ls, especially the double ones, run into the carets, he has concluded that they must serve some special and important purpose.

"We have been told upon high authority that the carets are illusions, and could not possibly be seen, as the planet is so distant from us. But the fact remains that they have frequently been seen and drawn; they always appear the same, and are never seen except in connection with ca.n.a.ls which join dark areas. These dark areas, I may say, are believed to be the beds of ancient seas, from which the water has long since departed.

"In connection with all these disputed lines and markings it has often been urged that though they are seen through comparatively small telescopes they are not seen when a very large instrument is used; and it has also been said that observers, knowing what they wished to see, simply imagined they did see it. We have, however, abundant proof that both these arguments are unreliable and incorrect.

"It is a well-known fact that when a faint object has been once seen through a telescope, others are able to see it through a smaller instrument. This was the case with the satellites of Mars, which have been seen with much smaller instruments than that used to discover them.

"The fact that such objects are really seen is proved by the observer marking them on his drawing in their correct position, although they may have moved from the point at which they were originally seen.

"I will give you an ill.u.s.tration of the ease with which it is possible to overlook something that should be clearly visible to you, yet it is not seen by you until your attention is called to it by some one else.

Almost every one has had some such experience:--

"You may have on the front of your coat a small stain, or grease-spot, in a position where you could plainly see it, yet might wear the coat for days or even weeks in complete unconsciousness of the existence of the stain until some one pointed it out to you. After that you cannot look at the coat without seeing the stain, and it becomes so persistently obtrusive that you are compelled to have it removed. There is, however, no imagination about your seeing the mark."

John here said to me: "Professor, I noticed you said that many who do not believe in the actuality of the lines and markings on Mars frequently refer to the fact that, while they are stated to be seen through small telescopes, they are quite invisible through a very large instrument, and they regard this as proving that the lines or markings do not exist. Is there not something in this argument?"

"Well, John," I replied, "the argument sounds not only plausible, but reasonable, and inexperienced persons might use the argument, believing it to be a sound and good one. I must, however, confess that I have been surprised to see this argument used by persons who must surely know that there is no weight in it at all.

"It is well known to all practical observers, and indeed to all who have studied optical matters, that, for several reasons, very large telescopes are quite unsuited for the observation of fine planetary detail.

"The real advantage of these enormous instruments lies in their great 'light-grasp,' which enables observers to see very faint points of light, such as small satellites of planets, faint stars, double stars, distant comets, or nebulae, which could not be seen with a smaller instrument necessarily having less 'light grasp.' Yet this very excess of light, which is the great advantage of a large instrument, is one of the things that spoils the definition of faint planetary details; it drowns them all out, or 'breaks them up.'

"Again, these large instruments are much more liable than smaller ones to what is termed 'chromatic' and 'spherical' aberration; and this also is detrimental to definition. No very large refractor is entirely free from these defects.

"Another objection is that, in using such large and long-focussed instruments, a much higher power must necessarily be employed than in the case of smaller instruments. This high power magnifies all the little movements and disturbances in our atmosphere to exactly the same extent as it magnifies the object looked at, with the result that these disturbances blur out all fine detail. The ca.n.a.l lines on Mars could never be seen in such circ.u.mstances. If the object were looked at through a smaller instrument, with lower power, it might be fairly well seen, for the atmospheric disturbances would not be magnified to such an extent as to spoil definition.

"There are very few nights in the year when these immense instruments can be used to advantage on the planets, whilst a smaller instrument might define well three or four nights out of every six. It is on record that the user of Lord Rosse's great reflector stated that there were only about three nights in the year when its best definition could be obtained; and its use has produced very meagre results, compared with what had been antic.i.p.ated.

"It is also almost universally recognised that in using these great instruments, whether for photography or for the visual observation of fine detail, it is absolutely necessary to stop down the aperture to a very large extent, by reducing it to about 12 inches in diameter or even less. The big telescope is thus really converted into a small one of long focus.

"There is, in addition, the acknowledged fact that nearly every discovery of new detail on planets has been made with a comparatively small telescope, although the same objects may have been under constant observation for years with big telescopes. The new detail was never noticed until after it had been seen with a smaller instrument, and perhaps only then when atmospheric conditions were unusually good.

"As an instance, I may mention that the faint 'c.r.a.pe ring' of Saturn was seen by Dawes when using an 8-inch aperture to his telescope; yet it had never been discovered with the large instruments, although the planet is one that is under constant observation when in a position to be seen.

"I could give innumerable instances of similar cases, but enough has been said to show that because some object cannot be seen in a very large telescope, it is no proof at all that the object does not exist.

"Amid the chaos of varied, and often self-contradictory, theories respecting Mars--some abandoned by their own authors; others in which facts and conditions had to be a.s.sumed for which there was not only no evidence, but actual disproof by many recorded observations--Professor Lowell's conceptions stand out clearly and boldly.

"They are all founded on the results of prolonged and systematic work in the observation of the planet, not only by himself but by numerous colleagues--work in which many of his critics have had little or no experience under favourable conditions. His conceptions fit in with observed facts with all the accuracy of the pieces in a child's picture puzzle; whilst his logical deductions are supported and enhanced by his wide knowledge of physical science and planetology.

"Yet, as I have both heard and read, his views and discoveries have been described as 'sensational,' 'fanciful,' 'fairy tales,' and by other terms which I would rather not quote.

"Underlying some of these objections there seems to be an idea that some reason _must_ be found for opposing anything and everything which would tend to indicate the possibility of intelligent life existing upon any other planet than the earth; although it is difficult to understand why such a possibility should be so abhorrent. It is a view that does not commend itself to me, but I need not say more on that point.

"Nicola Tesla, the great electrician, is, however, convinced of the existence of life upon Mars, and he has expressed in very emphatic terms his opinion of the opposite view, which, however, I refrain from quoting. He says that Mars must have pa.s.sed through all terrestrial changes and conditions, and that the whole arrangement of the ca.n.a.ls, as depicted by Professor Lowell, would seem to be artificially designed. He then goes on to state that he has discovered electrical disturbances on the earth which must have come from Mars and no other planet.

"In the treatment he has received from some of his smaller critics (whose vehemence is usually in inverse proportion to their knowledge of his work and writings) Professor Lowell has had an experience similar to that of many other observers who have done good work.

"If an observer be blessed with the happy combination of good eyesight, a good instrument, and favourable atmospheric conditions, and publishes writings and drawings showing that he has seen something which has not previously been observed, he at once becomes a target for captious critics who seem to be under the impression that all astronomical knowledge begins and ends with themselves, and that anything they cannot see does not exist. It matters not that the observer attacked may have given months to particular observations where his critics have only spent a few hours: he is told that his drawings are incorrect and do not represent the planet; that they may be works of art, but do not represent facts; that he possesses a very vivid imagination, and so on.

This procedure may be persisted in until at last the victim either turns and rends his critics or ceases to publish his drawings or records, to the great loss of many others who take an intelligent interest in his work.