I WISH to call your atten tion at some length to th e magnitude of the solar system and the relative situation of the sidereal heavens. To comprehend such enormous distances as those which separate us from the nearest of the fixed stars is, in an absolute sense, ari impossibility. The human mind is not large enough to grapple successfully with the mighty problem in- Ui-fclum; persons to the square mill', Austria-Hungary: J71 perrons to the square mile. Great Britain and Ireland: 312- It'-TMuns to th<: tlJuare mile, Spain: 90 pt'ftoOns to the square mile. ttalyn 213 perlJoOfU to the.Quatt • mile. European kuwla: 4J lo tbe square mile. German Empire ?37 pera tlie_square mile. ^^m Part. of Europe: f>7 to the 8fuare mile., Fig. 3.—These ten squares show the density of population ill Europe; illustrated by the number of persons. i. e.. dots to each square mile of the various countries named. volved. A long array of figures carries with it no definite i dea of the actual distance which they represent. But we may show some device, perhaps, which will help in considering the matter. Suppose a map of these United States were drawn on a space not large r th an yourthumb nai l. On such a map the commonwealth of Massachusetts would be but. a speck and yet relatively the map would be correct. So we may represent the solar system, approximate^. In constructing maps and plans. a certain scale is used—as so many feet or iniles to an inch. Now, using only round numbers. which are sufficiently accurate for our purpose. we say that the planet Neptune, the outermost known mem bei' of our system, is 2,800,000,000 miles from the sun. So if we use a line twenty-eight feet lon?, each single foot will re present one hundred million miles. On such a scale it would req ui re a po werfu l microscope to see a map of the United States at. all. But. we put a bead at each end of thi s line, one re presenting the sun, the other Neptune. Between the two, other beads will represent the other planets. One nearly four inches from that representng the sun will be Mercury; about seveninches, Venus; eleven inches, the earth; seventeen inches, Mars; about five feet, Jupiter; nine feet, Saturn; eighteen feet, Uranus; with Neptune at the end. This device shows approximately the relative distances of the principal planets from the sun. The asteroids lying between Mars and Jupiter are not represented, neither are any of the twenty-odd moons belonging to the system. To represent the size of the planets is not practicable. On this scale of one hundred million miles to one foot, a small shot would be large enough to represent the sun. As 1. he sun is one j thousand times as large as Jupiter, the giant of the system, itself one thousand times as large as this earth, you can understand that any object small enough to represent a planet could only be seen by the aid of a powerful microscope. On this scale a circle: fifty-six feet in diameter would include the orbits of every member of the solar system. When we look up at the stars on a clear night, the: vast majority of objects in sight are sums, many of ! them much larger than our own sun. To ordinary eyesight, with a clear horizon, about fifteen hundred are seen at one time. How far from us are they ? On this scale of 100,000,000 miles to one foot, the nearest would be about seventy miles. The approximate dis- I tance of only about twenty are known. As already stated, the attempt to give their distances in miles is ! meaningless. And the distance of only a small frac- tion is even approximately known. In the present I state of knowledge it cannot be. Our measuring de-1 vices are not equal to the task. As well try to measure the ocean with a pint dipper. The usual method is to give the number of years it [ takes light to reach our system from them, or, as it is called, their distances are expressed in “light years.” Light passes through space with the velocity of about; 185,000 miles each second of time. The light of the sun is about eight minutes in coming to us. It requires nearly four hours for the light of the sun to j reach Neptune. But it takes about seven years for the light to reach us from the nearest fix:ed star visible in this latitude, namely, the star known as “61 Cygni.”, in the constellation of Cygnus, the Swan. The light of the great Sirius, sometimes called from its superlative brightness the “King of the Suns,” is about fifteen years in coming, while that of the North Star is fifty. If the sun were represented by a globe two feet in diameter, the earth on the same scale would be a ball as large as a pea. about 220 feet distant. Jupiter would be the size of an orange one-third of a mile, with Nep tune the size of a boy's marble one and one-fourth miles distant. On this scale a circle two and a half miles in diameter would include all the members of our solar system; but on this scale the nearest fixed stars would be nearly as distant as is our moon. The sizes of the fixed stars are measured by their j brightness. The actual disks of the planets are seen, but no telescope has been constructed which shows the j disk of a star. What we do see is the beam of light,; which. penetrating space, comes to our eyes after its long flight, it may be of centuries. We also know that: on approaching a star its brightness would be increased ! and diminished if we went farther away. Now sup-: pose that retaining your consciousness, you could go: out, far beyond the confines of our solar system, to a point one thousand times as far beyond Neptune as Neptune is from the sun. But first consider the fact that when you arrived at Neptune you would receive only about one one-thousandth as much light and heat from the sun as we receive on earth. At that distance the sun would appear only a trifle larger than the planet Venus sometimes appears to us. It follows: that, by increasing that distance one thousandfold, we should dwarf the sun to the apparent size of a small star. Consequently we should receive little light from him; but even at that great distance we should not have approached near enough to the thousands of suns in the direction we were going to receive from j them any appreciable increase of light, and consequently we should be in a zone of perpetual darkness, unrelieved by any light except that which we know as starlight. When you look up at night and view the “countless hosts of Heaven” which stud the blue vault above you, consider that you are looking through that vast zone of endless night—that void of densest blackness, cold and silent forever. No human stranded 011 an island ' in the midst of a broad and unnavigable ocean would j be more utterly alone than is our solar system. But is it a void ? Is any part of the domain of the Great Creator, so unspeakably immense as this space between us and the stars, a waste ? The question of the habitability of “other worlds than ours” has been for generations a fruitful theme of speculation. The weak point in such discussions seems to me to be in the assumption that if any other planet were inhabited,'it must of necessity be with beings not materially unlike ourselves. 1 cannot thus limit the attributes of the Great Creator. The vast variety in all known forms of life on our planet ought, it seems to me, to be taken as a hint, at least, that He is able to call more than one form of “human” into being. Indeed, it does not require any great stretch of the imagination to conceive of intelligent beings, quite unlike ourselves in form and material, but equipped with senses so keen that our senses of hearing, and sight, and touch were dull in comparison. It is the spirit and not the material that thinks, and reasons and knows; and.spirit takes no cognizance of heat and cold, light or darkness. Observations have already furnished evidence that a dark sun is a member of our system. The light and | heat of our sun are vitally necessary to existence as j we know it. But were it wholly dark and cold, its i attractive force would not be affected, and all the planets, themselves also dark and cold, would continue to perform their revolutions, as they have for ages past. May it not be possible, then, that outside of our system, and between us and the area filled with the visible stars, there may exist dark suns surrounded by families of dark planets, but peopled by beings as intelligent, as advanced, as happy, as well informed in regard to His works and His attributes as we are ? We call our moon dead and lifeless. The planet Mars has, we know, progressed far in the same direction. From analogy, we believe that no life, as we know it, could exist on the asteroids, and probably ' . not on the moons of other planets. Have we the assurance to claim that all these untold millionsof suiis were created after our system had a being', and were i created for no other purpose than to interest the inI habitants of this comparatively insignificant speck | which we call the earth ? For myself, I cannot doubt ' that systems came into being as ours did, and passed through the several stages of planetary life, reaching the stage of darkness and refrigeration, untold ages before our system passed the nebulous period. j Another consideration in connection with the question of varieties of sentient life may be named: all the life on the earth, animal and vegetable, is subject to change, depending upon a change in the conditions by which it is surrounded. Plants and animals increase in vigor and mental characteristics, or decrease in the same qualities when removed to locations more or less favorable to their development. Two children: born of the same parents in the temperate zone re- i move, one to the tropics, the other to the frigid zone. After a few generations, the descendants of these children will be quite unlike. In like manner must mankind change as in the process of the ages the surroundings change. But the changes wrought by natural causes take place very slowly. No one would think of questioning the statement that this earth is continually growing colder. The length of time is approximately known when this earth, having parted with a portion of its heat, when the waters of the oceans have been partially absorbed, will be unable to support life in the manner familiar to us. But while the earth, during long ages, is changing, life will also be changing to conform jto the altered conditions. And this process is so gradual that during the period covered by authentic history slight evidence of such change can be found. Scientists are agreed that life, as we know it, does not exist on our moon. Was it ever otherwise ? From analogy I cannot doubt that the moon was once inhabited and may be so still. I take it for granted that no one will question the truthfulness of the adage that “like causes produce like effects.” Growth on the surface of the earth is caused by heat, light, moisture and a proper soil. Given these conditions, and life must exist. If you could find some island of the sea, hitherto undiscovered, possessing these requisites, you would know in advance that there you would find life also. Now, according to the doctrine of the nebular hypothesis, substantially accepted by scientists the world over, our sun and every member of his planetary family were originally in one mass. If one of our good housekeepers should take a quantity of flour and other proper ingredients, make the whole into one mass of dough, and from that mass mould loaves of different sizes. leaving the larger quantity as a final loaf, it would roughly illustrate the several members of our solar system in one particular. The last and largest loaf would represent the sun; the smaller, the several planets. The small loaves would require less time than the large in cooking, but in their ingredients they would be substantially alike. From the original mass of matter now forming our solar system came first Neptune, then Uranus, followed by Saturn. Jupiter, Mars, the earth,Venus and Mercury, with the remaining and much the largest mass, the sun. Some of these newly-born planets, in turn, threw off the material now seen in their respective moons. But accepting the difference caused by the operations of nature upon masses of different sizes, they must be substantially alike; and long years after the acceptance of the doctrine of the nebular hypothesis, the spectroscope comes in to corroborate it by showing that not only in our solar system, but in the sidereal universe as well, substantially the same elements exist. The sun, as well as the earth, has. its salt, iron, hydrogen, magnesium, copper, zinc, nickel and many other elements. This fact is of great importance in considering the question of the habitability of “other worlds than ours.” The moon is our very nearest neighbor. The next nearest, Venus, is more than one hundred times as distant. How much do our people know about the moon ? For ages it has been the object of a great amount of superstition and error. It was held to possess evil influences over mankind. The word “lunatics” comes, I believe, from the word luna, the moon. For many years it was supposed to rule the weather. So powerful and widespread was this delusion that the celebrated astronomer Herschel made continuous observations for years to detect, if possible, the basis of the claim. But notwithstanding the fact that his conclusions were positive that it had no influence upon the weather, we have some still who hold to the fallacy. In the meantime, the really important work of studying its physical geography by the scholars in our corn- mon schools has been wholly neglected. Our children study the geography of the earth, with manifest advantage. They can name the states, tell their location, boundaries, etc. Suppose from some elevation they could survey the whole hemisphere, trace the courses of the rivers, mountain chains, see the great lakes and other features. Would it not be permanently valuable, as well as interesting ? Now the surface of the moon is covered with objects of great interest. There are to be seen chains of mountains, isolated peaks, areas believed to have been the beds of former oceans, volcanic craters ranging in size from those which seem but a speck to those one hundred miles in diameter. In the past, the volcanic activity on the moon must have been on a scale to which our earth furnishes no parallel. Although the moon is now apparently cold and lifeless, it does not follow that nothing more can be learned of its past and present history. It is an attribute of weak human nature, perhaps, to consider that whatever is foreign to or unknown by themselves cannot be worthy of profound consideration. Because the surface of the moon is quite unlike that of the earth, because no evidence has been detected that she possesses an atmosphere or water, because such observations as have been made in the past do not show thatchanges havecertainlytaken place upon its surface, the conclusion seems to have been reached that it is not worth while to study it systematically. with proper instruments and under favorable conditions. I think this is a mistake, and, despairing of any movement of a public character to bring about so desirable a consummation, I hope that some time and somewhere some man of large means will endow an institution for this express purpose. Some day it may be told that evidence is in hand that the body now given over to superstition and juvenile entertainment is in reality the abode of beings superior to those who arrogate to themselves the title of '• Lords of Creation.” From the nearer let us pass at a bound to the farthest known bodies. Point the telescope now mounted on Mt. Hamilton in one direction and observe the most distant star which its thirty six inch glass will pick up. Then turn it in the opposite direction, and do the same. How far apart are the two bodies thus seen ? No one can tell, but they may be so distant that it requires millions of years for the light of one to pass to the other. And remember that the whole sphere outlined by these stars is studded with suns the number of which no student of astronomy has as yet been bold enough to estimate. That they number hundreds of millions is within the range of probability. And if so many suns, how many planets may there be ? The mind shrinks from the task of attempting an answer. Our own system, with its comparatively small sun, numbers, as far as is now known, nearly four hundred. Suns of much greater magnitude may be the centers of planetary families numbering thousands. Go down to the sea shore, and picking up a grain of sand, ask yourself what proportion it bears to all the sands on the shores of all the oceans on earth. The problem is as easy to answer as that of the proportion which this world bears to the habitable and inhabited worlds within the visible universe of the Great Creator. At first bewildering in the immensity and glory of the conception, in time it becomes a source of in^pressible satisfaction and reverence. Thousands of years ago the Chaldean shepherds saw the stars as they rose over their eastern plains. Among them they saw the planet Mars, as clearly as they saw the moon. But by the unaided vision little could be positively known of any of the heavenly bodies. When in the course of time instrumental observation became possible, all were subjected to scrutiny by the keenest observers in the astronomical world. The markings on the moon, however, were much more plainly seen than on Mars. A glass which would show satisfactory details at the distance of 240,000 miles might not do so on a planet never less than about 35,000,000 miles. But the question of the habitability of either was equally in doubt and has remained so until this year, and to many remains so still. The planet Mars has, however, been a favorite object for study by many astronomers. Seventeen years ago, a keen eyed Italian astronomer published an account of certain markings which he had seen. These markings were perfectly straight lines. running for a thousand miles, more or less, in various directions. He gave them a name which in English was translated “canals.” Other astronomers with much larger telescopes could not see them and refused to believe the published accounts. But after a lapse of nine years, others did see them, and not only sa w them, but found the planet partially covered with them like a network. They were estimated to be from twenty miles wide to several times that width. The idea of a canal or straight waterway thirty or forty miles wide and a thousand miles long was preposterous. Fortunately, however, we have scientific enthusiasts who are not. to be deterred from the attempt to solve difficult problems. Armed with the best instruments made by our most advanced mechanics. mounted in an observatory located in the high and dry region of Arizona, Mr. Lowell and his staff set down to pursue their investigations with sublime patience and courage. Carefully prepared maps of all the markings were made, and all the phenomena observed and studied. The conclusion substantially arrived at by them was that these markings were not water but areas of vegetation. In short that the entire svstem of the so-called canals was one vast and system of irrigation. I will not say that an absolute conclusion has been reached, but it is, I think, safe to say that at this moment astronomers are in possession of evidence of the most pronounced character that Mars has been inhabited; and if it has been, why not now ? It is a matter for national pride that a young American should be the first man to make the announcement that the markings seen for years by keen visioned observers, in many lands, are areas of vegetation, which develop as our crops do in the spring.and disappear, as also they do, in the fall, made possible only by the stupendous system of irrigation covering a territory larger than this entire country. I want to call your attention to one consideration which seems to me important. The water ways, in whatever form, which form this network on Mars, in many cases run in a straight line for a thousand ir,iles. The engineering ability to accomplish this is second to nothing ever done on this earth. Now by the unaided vision no human being could run an absolutely straight line for hundreds of miles, especially when on a curved surface like that of a planet. Only by the aid of instruments of precision as reliable as those used by our engineers could this work be accomplished. And if they have telescopes at all, as their works prove they must have, why not instruments large enough to look at this earth in detail, as our astronomers are looking at them ? Untold ages ago, Mars was in a condition analogous to the condition of this earth now. With the passing of the time, have not their people been making progress in all the arts known to them ? And quite possibly some thousands of years ago they were watching this planet through superior instruments, speculating perhaps among themselves whether their nearest neighbor, so shrouded in clouds and vapors, could possibly be the abode of intelligent beings. We may imagine that they, living in a climate uniformly mild and pleasant, free from storms and disastrous gales, might have concluded that their “bigger brother” world was a totally unfit place for habitation; or if inhabited at all, probably by “monsters of the briny dpep,” or organisms far below themselves in the scale of being. Perhaps in that remote period they exhausted their resources in trying to signal the inhabitants of earth, in case there were any such, and discouraged at the lack of any response, came to the con- c! usion that it was wise to let so unpromising a subject severely alone.