MISCELLANEOUS PAPERS. 367 



more or less defective drawings to represent astronomical phenomena. 

 What the imagination may depict, let an ancient sketch of a comet, 

 with its hideous train of swords, knives, and bloody heads, attest. 

 The modern astronomer is not so unreliable as that, but an inspection 

 of various drawings of the sun's corona, or the nebula of Orion, will 

 show that tbe personal equation must be taken into account. The 

 camera, however, is absolutely without prejudice or predilection. 

 Photographs are of inestimable value for future reference in making 

 comparisons to detect possible changes. In addition to this, the pho- 

 tographic plate is more sensitive than the eye, and is able to accumu- 

 late the impressions received from hours of exposure, while the eye 

 tires after a few minutes of close observation. The photographic 

 chart of the whole heavens, now being prepared, will accurately locate 

 and give the comparative magnitudes of many millions of stars. The 

 supposed 8000 or 9000 nebuhij, visible with the best telescopes, have 

 been increased twentyfold by a happy experiment of Professor Kee- 

 ler in photographing without the eyepiece. 



The spectroscope, the plaything of the physicist a half-century ago, 

 has become the magic wand of the astronomer. With it he analyzes 

 the constituents of stars away out on the fringe of the universe, so 

 distant that fleet-footed light takes hundreds and even thousands of 

 years to traverse the vast gulf, and he does it as easily and accurately 

 as if they were on his laboratory table. The unseen atmospheres and 

 the physical conditions of these bodies are also revealed. In this way 

 the wondrous unity and identity of the universe have been established, 

 perhaps the greatest single feat of modern astronomy. Many of these 

 stars are shown to be unfinished suns, whose vast bulks are due to the 

 uncondensed nebulae or " fire- mist " or meteoric matter of which they are 

 composed. Giant Arcturus, for instance, has been estimated to be a 

 million times the size of our sun. If this estimate is correct, and the 

 earth were represented by a sand grain, and the Omnipotent should pour 

 out of His mighty hand ten such world sand grains per second, it would 

 take over 4000 years for enough earths to trickle out to make one 

 Arcturus ! 



A few stars had been suspected of having dark companions or 

 satellites revolving around them even before the advent of the spec- 

 troscope, but this instrument has definitely shown that a considerable 

 fraction of the stars have such planetary bodies of notable size circling 

 about them, thus completing the analogy with our own solar system. 

 By implication, most if not all of the hundreds of millions of such 

 luminaries are attended by such invisible satellites. This revelation of 

 unseen worlds is little short of miraculous. The human conception 

 fails to grasp the magnitude of such a starry universe. 



