December 10, 1920] 



SCIENCE 



547 



Said the astronomer to the party of visitors : 

 " The object which you will see through the 

 great telescope this evening is the star cluster 

 in Hercules, the finest cluster in the northern 

 sky. Without the telescope, by naked eye, this 

 cluster may be seen if the observer knows 

 exactly where to look and has first-class eyes, 

 but he will see it as apparently a single star 

 on the limit of vision, so faint that many 

 eyes will not see it at all. The telescope 

 separates the cluster into a multitude of stars. 

 If you had the time to count them, they 

 would number fully six thousand, closely 

 grouped in the center of the cluster, but thin- 

 ning out as you approach the edges. This 

 one object, then, which to the naked eye seems 

 to be a single star on the limit of vision, con- 

 sists of at least as many stars as the eye alone 

 is able to see in the sky as a whole, northern 

 and southern skies, summer and winter skies 

 combined, and we do not doubt that long pho- 

 tographic exposures on the cluster, with a 

 large reflecting telescope, would record many 

 more than six thousand. Each of these stars 

 is a sun and probably every one of those 

 which you will see is larger than our sun,, for 

 we are observing merely the brightest mem- 

 bers of the system. We do not know whether 

 these suns have planets revolving around them 

 or not, as the cluster is entirely too far away 

 for us to see such planets, but planets prob- 

 ably exist there in great numbers; possibly 

 there are planets revolving around all of those 

 stars; possibly and probably there are moons 

 revolving around the planets; and finally, 

 there may be life, vegetable, animal, intelli- 

 gent life upon those planets." 



One of the visitors upon descending from 

 the observing chair, much interested, ques- 

 tioned the astronomer : " Did you say those 

 stars are all suns ? " " Yes, sir." " Did you 

 say that those stars are really larger than our 

 sun, on the average ? " " Yes, sir." " Can you 

 give me an idea how large our sun is ? " 

 " Well, if it were a hollow shell, of its present 

 size, you could ixjur more than a million 

 earths into it, and there would still be much 

 unoccupied space between the earth balls." 

 "You say, there are possibly or probably 



planets revolving aroimd many of the cluster 

 stars?" "Yes, sir." "And many of those 

 planets may be inhabited ? " " Yes, sir." 

 " Well then, I think it does not matter very 

 much whether Eoosevelt or Taft is nomi- 

 nated next week at the Chicago Convention." 



Of course the visitor's interest in the out- 

 come at Chicago was just as keen as ever, 

 but he had evidently received a valuable 

 lesson concerning man's place in nature. 



The wonders of our sun are many and most 

 remarkable, and are but little known. I have 

 referred to its enormous size. The quantity 

 of heat which the sun is radiating into sur- 

 rounding space, to the earth, to Mars, and to 

 all other objects which intercept its rays, is 

 stupendous and not to be comprehended by 

 the astronomer or the man of affairs. It is, 

 and has been, the source of all the energy 

 upon which we draw, save only a negligible 

 residual. A great quantity of heat is indeed 

 stored up in the interior of the earth, but it 

 reaches the earth's surface in such minute 

 quantities that in all practical details of life, 

 save to those who labor in deep mines, or live 

 near volcanoes, or are interested in hot 

 springs, this source of energy may be neg- 

 lected. If this statement should be difilciilt 

 to accept, let your thoughts travel to the south 

 pole of our planet. What does the interior 

 heat of the earth do for that region? The 

 antarctic continent's perpetual covering of ice 

 and snow is unaffected by it, nor does the 

 actually enormous quantity of solar heat fall- 

 ing upon that continent suffice to remove the 

 white mantle. If aught should intervene to 

 cut off the sun's energy from the earth for 

 one short month, the tropics would attain to 

 a state of frigidity to which the south jwlar 

 continent, as now observed, would be a rose 

 garden in comparison. 



It is the sun's heat which grows the farm- 

 er's crops, the trees of the forest and all vege- 

 tation. The coal deposits upon which we 

 draw to-day for the running of trains, ships, 

 factories and rolling mills, are but the solar 

 energy of an earlier age, compressed, trans- 

 formed and preserved for our comfort and 

 power. In the mountainous regions of our 



