242 



THE POPULAR SCIENCE MONTHLY. 



contents of Prof. Dana's volume, but mean 

 to do so in a future number ; yet we cannot 

 forbear quoting a pleasant passage referring 

 to a man of whom much is now vehemently 

 said, both in praise and disparagement : 



" Our cruise led us partly along the 

 course followed by Mr. Charles Darwin 

 during the years 1831 to 1836, in the voy- 

 age of the Beagle, under Captain Fitzroy ; 

 and, where it diverged from his route, it 

 took us over scenes, similar to his, of coral 

 and volcanic islands. Soon after reaching 

 Sydney, Australia, in 1839, a brief state- 

 ment was found in the papers of Mr. Dar- 

 win's theory with respect to the origin of 

 the atoll and barrier forms of reefs. The 

 paragraph threw a flood of light over the 

 subject, and called forth feelings of peculiar 

 satisfaction, and of gratefulness to Mr. Dar- 

 win, which still come up afresh whenever 

 the subject of coral islands is mentioned. 

 The Gambier Islands in the Paumotus, which 

 gave him the key to the theory, I had not 

 seen ; but on reaching the Feejees, six 

 months later, in 1840, I found there similar 

 facts on a still grander scale and of more 

 diversified character, so that I was after- 

 ward enabled to speak of his theory as 

 established with more positiveness than he 

 himself, in his philosophic caution, had been 

 ready to adopt." 



SpECTRrjM Analysis, in its Application to 

 Terrestrial Substances, and the Physical 

 Constitution of the Heavenly Bodies. 

 Familiarly explained by Dr. H. Schel- 

 len, Director der Realschule I. 0. Co- 

 logne. Translated from the second en- 

 larged and revised German edition, by 

 Jane and Caroline Lassell. Edited, with 

 Notes, by William Huggins, LL. D. With 

 numerous Woodcuts, Colored Plates, and 

 Portraits ; also, Angstrom's and Kirch- 

 hoff ' s Maps. 455 pages, 8vo. D. Ap- 

 pleton & Company. 



In his late work on the sun, Mr. R. A. 

 Proctor, author of " Other Worlds than 

 Ours," says : " The reader is referred, for 

 fuller details than there is here space for, 

 to Dr. Schellen's work on ' Spectrum Analy- 

 sis,' the English edition of which is now 

 preparing for publication under the able 

 supervision of Dr. Huggins. This work 

 ' will be specially worthy of very careful 

 study in all matters relating to the spectral 

 Analysis of the sun." This long-expected 



work, which has been so eagerly looked fo 

 by those who desire a popular and authori- 

 tative exposition of this beautiful subject 

 has now appeared, and is republished in 

 this country at half the English price. An 

 able writer m the London Spectator thuA 

 speaks of it : 



In the whole history of science there 

 is nothing more wonderful than the discov- 

 ery or invention (it would be difficult to say 

 which is the more correct term) of spectrum 

 analysis, and the sudden advance of the 

 new method of research into a foremost 

 position, among all the modes of scientific 

 inquiry. If we take up at random any re- 

 cent scientific work, whether on astronomy, 

 or chemistry, or meteorology nay, even 

 though it treat of subjects like entomolo- 

 gy, botany, and conchology, which seem as 

 far as possible removed from optical prob- 

 lems we cannot turn over its pages with- 

 out finding more or less copious reference 

 to the prismatic analysis of light. Yet, 

 thirteen years ago, spectrum analysis had 

 no existence whatever as a mode of scien- 

 tific inquiry. It was a subject for research, 

 not a method of research, and there were 

 not a few who regarded it as a subject al- 

 together intractable, while scarcely any be- 

 lieved that it would become the means of 

 advancing our knowledge to any important 

 extent. 



The history of the sudden advance of 

 this great problem into the position of a 

 great solver of problems is full of interest. 

 Not five years had passed from the day 

 when Kirchhoff announced the true mean- 

 ing of the dark lines in the solar spectrum, 

 before Huggins and Miller were telling as- 

 tronomers of the terrestrial elements exist- 

 ing in the stars. Then the great secret of 

 the gaseous nebulas was revealed by Hug- 

 gins, and soon after the structure of comets 

 began to be interpreted. Nor had chemists 

 been idle in the mean time. In 1861, Bun- 

 sen and Crookes, by means of the new 

 analysis, had detected three hitherto un- 

 known elements, ciesium, rubidium, and 

 thallium, and, in 1863, Reich and Richter 

 had discovered a fourth new element, in- 

 dium. The importance of the new mode, 

 of research in all problems of chemical 

 analysis, as a delicate test for determining 

 the presence of poisons, as a means of ini- 



