208 THE POPULAR SCIENCE MONTHLY. 



labored, by demonstrating, in 18G0, the law which is the theoretical 

 basis of the chemistry of the heavens. Kirchhoff, with admirable 

 frankness, is careful to say that this law had been anticipated by 

 others, especially by Angstrom and Balfour Stewart, although it had 

 not been sharply stated or severely proved. It is a singular fact that 

 the mechanical explanation of the law, as it has been expounded by 

 Kirchhoff, Angstrom, and Stokes, was partially enunciated one hun- 

 dred years ago by the mathematician Euler, when he said that every 

 substance absorbs light of the special wave-length which corresponds 

 to the vibration of its smallest particles. The 11th of July, 1861, will 

 be ever memorable in the history of science as being the day on which 

 Magnus read, before the Berlin Academy, Kirchhoff's memoir on the 

 chemical constitution of the sun's atmosphere, and the existence in it 

 of familiar substances found upon the earth. Speedily, spectroscopes 

 were multiplied, modified, and improved, and became indispensable 

 auxiliaries in the workshop, the laboratory, and the observatory. It 

 is not necessary to enlarge upon what this instrument has done for 

 common chemistry, in hunting out the minutest traces of common 

 substances and detecting new ones. The physician, the physiologist, 

 the zoologist, the botanist, and the technologist, have shared with the 

 chemist and the physicist the services of this powerful analyst. But 

 it is the highest prerogative of the spectroscope to be able to make a 

 chemical analysis of celestial bodies, upon the single condition that 

 they give to it their light. Polarization can only say whether any 

 portion of this light is reflected. The motions which the telescope 

 uncovers may decide in favor of a central attraction, but it is silent 

 as to the intensity of this attraction unless the moving body belongs 

 to the solar system. The universality of a gravitation may be proved, 

 but not the universality of the very gravitation which pervades our 

 own system, except by an argument from analogy. We see that one 

 star differs from another star in glory. But what the other differences 

 or resemblances are we know not, without the spectroscope. Hence- 

 forth astronomy possesses a new instrument of discovery, and also a 

 new tribunal to which all speculations about the sun and the stars, 

 the aurora and the zodiacal light, the meteors and the comets, must be 

 brought and by which they must be judged. 



I leave it to the naturalists to assign a value to the alleged antici- 

 pations of Darwin by the geometer Manpertuis, who was said to have 

 died just before he was going to make monkeys talk. The whims and 

 conceit of Lord Monboddo are not worthy of notice. Lamarck began 

 life as a soldier, was a meteorologist as far and as long as Napoleon 

 would allow him to be ; perhaps he was a botanist from choice, but 

 he was made a zoologist, in spite of himself, by the revolutionary Con- 

 vention. He was as brave in science as in war ; but he expected to 

 create it, by a simple effort of thought. Having demolished the mod- 

 ern chemistry, he turned his iconoclastic zeal into natural history. 



