They made the further important discovery that the lines do not stop short at the dark regions of the planet's surface, as. .h.i.therto believed, but go right on in many cases; the curvature of the lines being unaltered.

Lowell is an uncompromising advocate of the "ca.n.a.l" theory. If his arguments are correct we have at once an answer to our question, "Are there other minds than ours?"

We must consider a moment Lowell's arguments; not that it is my intention to combat them. You must form your own conclusions. I shall lay before you another and, as I venture to think, more adequate hypothesis in explanation of the channels of Schiaparelli. We learn, however, much from Lowell's book--it is full of interest.[1]

Lowell lays a deep foundation. He begins by showing that Mars has an atmosphere. This must be granted him till some counter observations are made.

[1] _Mars_, by Percival Lowell (Longmans, Green & Co.), 1896,

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It is generally accepted. What that atmosphere is, is another matter. He certainly has made out a good case for the presence of water as one of its const.i.tuents,

It was long known that Mars possessed white regions at his poles, just as our Earth does. The waning of these polar snows--if indeed they are such--with the advance of the Martian summer, had often been observed. Lowell plots day by day this waning. It is evident from his observations that the snowfall must be light indeed. We see in his map the south pole turned towards us. Mars in perihelion always turns his south pole towards the sun and therefore towards the Earth. We see that between the dates June 3rd to August 3rd--or in two months--the polar snow had almost completely vanished. This denotes a very scanty covering. It must be remembered that Mars even when nearest to the sun receives but half our supply of solar heat and light.

But other evidence exists to show that Mars probably possesses but little water upon his surface. The dark places are not water-covered, although they have been named as if they were, indeed, seas and lakes. Various phenomena show this. The ca.n.a.ls show it. It would never do to imagine ca.n.a.ls crossing the seas.

No great rivers are visible. There is a striking absence of clouds. The atmosphere of Mars seems as serene as that of Venus appears to be cloudy. Mists and clouds, however, sometime appear to veil his face and add to the difficulty of

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making observations near the limb of the planet. Lowell concludes it must be a calm and serene atmosphere; probably only one-seventh of our own in density. The normal height of the barometer in Mars would then be but four and a half inches. This is a pressure far less than exists on the top of the highest terrestrial mountain. A mountain here must have an alt.i.tude of about ten miles to possess so low a pressure on its summit. Drops of water big enough to form rain can hardly collect in such a rarefied atmosphere. Moisture will fall as dew or frost upon the ground. The days will be hot owing to the unimpeded solar radiation; the nights bitterly cold owing to the free radiation into s.p.a.ce.

We may add that in such a climate the frost will descend princ.i.p.ally upon the high ground at night time and in the advancing day it will melt. The freer radiation brings about this phenomenon among our own mountains in clear and calm weather.

With the progressive melting of the snow upon the pole Lowell connected many phenomena upon the planet's surface of much interest. The dark s.p.a.ces appear to grow darker and more greenish. The ca.n.a.ls begin to show themselves and reveal their double nature. All this suggests that the moisture liberated by the melting of the polar snow with the advancing year, is carrying vitality and springtime over the surface of the planet.

But how is the water conveyed?

Lowell believes princ.i.p.ally by the ca.n.a.ls. These are

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constructed triangulating the surface of the planet in all directions. What we see, according to Lowell, is not the ca.n.a.l itself, but the broad band of vegetation which springs up on the arrival of the water. This band is perhaps thirty or forty miles wide, but perhaps much less, for Lowell reports that the better the conditions of observation the finer the lines appeared, so that they may be as narrow, possibly, as fifteen miles. It is to be remarked that a just visible dot on the surface of Mars must possess a diameter of 30 miles. But a chain of much smaller dots will be visible, just as we can see such fine objects as spiders'

webs. The widening of the ca.n.a.ls is then accounted for, according to Lowell, by the growth of a band of vegetation, similar to that which springs into existence when the floods of the Nile irrigate the plains of Egypt.

If no other explanation of the lines is forthcoming than that they are the work of intelligence, all this must be remembered.

If all other theories fail us, much must be granted Lowell. We must not reason like fishes--as Lowell puts it--and deny that intelligent beings can thrive in an atmospheric pressure of four and half inches of mercury. Zurbriggen has recently got to the top of Aconcagua, a height of 24,000 feet. On the summit of such a mountain the barometer must stand at about ten inches. Why should not beings be developed by evolution with a lung capacity capable of living at two and a half times this alt.i.tude. Those steadily

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curved parallel lines are, indeed, very unlike anything we have experience of. It would be rather to be expected that another civilisation than our own would present many wide differences in its development.

What then is the picture we have before us according to Lowell?

It is a sufficiently dramatic one.

Mars is a world whose water supply, never probably very abundant, has through countless years been drying up, sinking into his surface. But the inhabitants are making a brave fight for it, They have constructed ca.n.a.ls right round their world so that the water, which otherwise would run to waste over the vast deserts, is led from oasis to oasis. Here the great centres of civilisation are placed: their Londons, Viennas, New Yorks. These gigantic works are the works of despair. A great and civilised world finds death staring it in the face. They have had to triple their ca.n.a.ls so that when the central ca.n.a.l has done its work the water is turned into the side ca.n.a.ls, in order to utilise it as far as possible. Through their splendid telescopes they must view our seas and ample rivers; and must die like travellers in the desert seeing in a mirage the cool waters of a distant lake.

Perhaps that lonely signal reported to have been seen in the twilight limb of Mars was the outcome of pride in their splendid and perishing civilisation. They would leave some memory of it: they would have us witness how great was that civilisation before they perish!

I close this dramatic picture with the poor comfort

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that several philanthropic people have suggested signalling to them as a mark of sympathy. It is said that a fortune was bequeathed to the French Academy for the purpose of communicating with the Martians. It has been suggested that we could flash signals to them by means of gigantic mirrors reflecting the light of our Sun. Or, again, that we might light bonfires on a sufficiently large scale. They would have to be about ten miles in diameter! A writer in the Pall Mall Gazette suggested that there need really be no difficulty in the matter. With the kind cooperation of the London Gas Companies (this was before the days of electric lighting) a signal might be sent without any additional expense if the gas companies would consent to simultaneously turn off the gas at intervals of five minutes over the whole of London, a signal which would be visible to the astronomers in Mars would result. He adds, naively: "If only tried for an hour each night some results might be obtained."

II

We have reviewed the theory of the artificial construction of the Martian lines. The amount of consideration we are disposed to give to the supposition that there are upon Mars other minds than ours will--as I have stated--necessarily depend upon whether or not we can a.s.sign a probable explanation of the lines upon purely physical grounds. If it is apparent that such

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lines would be formed with great probability under certain conditions, which conditions are themselves probable, then the argument by exclusion for the existence of civilisation on Mars, at once breaks down.

{Fig. 10}

As a romance writer is sometimes under the necessity of transporting his readers to other scenes, so I must now ask you to consent to be transported some millions

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of miles into the region of the heavens which lies outside Mars'

orbit.

Between Mars and Jupiter is a chasm of 341 millions of miles.

This gap in the sequence of planets was long known to be quite out of keeping with the orderly succession of worlds outward from the Sun. A society was formed at the close of the last century for the detection of the missing world. On the first day of the last century, Piazzi--who, by the way, was not a member of the society--discovered a tiny world in the vacant gap. Although eagerly welcomed, as better than nothing, it was a disappointing find. The new world was a mere rock. A speck of about 160 miles in diameter. It was obviously never intended that such a body should have all this s.p.a.ce to itself. And, sure enough, shortly after, another small world was discovered. Then another was found, and another, and so on; and now more than 400 of these strange little worlds are known.

But whence came such bodies? The generally accepted belief is that these really represent a misbegotten world. When the Sun was younger he shed off the several worlds of our system as so many rings. Each ring then coalesced into a world. Neptune being the first born; Mercury the youngest born.

After Jupiter was thrown off, and the Sun had shrunk away inwards some 20o million miles, he shed off another ring. Meaning that this offspring of his should grow up like the rest, develop into a stable world with the

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potentiality even, it may be, of becoming the abode of rational beings. But something went wrong. It broke up into a ring of little bodies, circulating around him.

It is probable on this hypothesis that the number we are acquainted with does not nearly represent the actual number of past and present asteroids. It would take 125,000 of the biggest of them to make up a globe as big as our world. They, so far as they are known, vary in size from 10 miles to 160 miles in diameter. It is probable then--on the a.s.sumption that this failure of a world was intended to be about the ma.s.s of our Earth--that they numbered, and possibly number, many hundreds of thousands.

Some of these little bodies are very peculiar in respect to the orbits they move in. This peculiarity is sometimes in the eccentricity of their orbits, sometimes in the manner in which their orbits are tilted to the general plane of the ecliptic, in which all the other planets move.

The eccentricity, according to Proctor, in some cases may attain such extremes as to bring the little world inside Mars' mean distance from the sun. This, as you will remember, is very much less than his greatest distance from the sun. The entire belt of asteroids--as known--lie much nearer to Mars than to Jupiter.

As regards the tilt of their orbits, some are actually as much as 34 degrees inclined to the ecliptic, so that in fact they are seen from the Earth among our polar constellations.

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From all this you see that Mars occupies a rather hot comer in the solar system. Is it not possible that more than once in the remote past Mars may have encountered one of these wanderers? If he came within a certain distance of the small body his great ma.s.s would sway it from its...o...b..t, and under certain conditions he would pick up a satellite in this manner. That his present satellites were actually so acquired is the suggestion of Newton, of Yale College.

Mars' satellites are indeed suspiciously and most abnormally small. I have not time to prove this to you by comparison with the other worlds of the solar system. In fact, they were not discovered till 1877--although they were predicted in a most curious manner, with the most uncannily accurate details, by Swift.

One of these bodies is about 36 miles in diameter. This is Phobos. Phobos is only 3.700 miles from the surface of Mars. The other is smaller and further off. He is named Deimos, and his diameter is only 10 miles. He is 12,500 miles from Mars' surface.

With the exception of Phobos the next smallest satellite known in the solar system is one of Saturn's--Hyperion; almost 800 miles in diameter. The inner one goes all round Mars in 7 hours. This is Phobos' month. Mars turns on his axis in 24 hours and 40 minutes, so that people in Mars would see the rise of Phobos twice in the course of a day and night; lie would apparently cross the sky