LITERARY NOTICES. 



*3i 



trust " The Open Court " will become a po- 

 tent influence favoring the reduction to a 

 scientific platform of the principles and 

 precepts of these great departments of hu- 

 man interest. 



We do not understand that the presen- 

 tation of the " Monistic philosophy " is in- 

 tended to make the successor of " The In- 

 dex " an organ of any theory of knowledge 

 or being ; for, while philosophy is not to be 

 disparaged, it is far better to stand firmly 

 upon science, and thence reach outward and 

 onward to philosophy with much caution. 

 If the prime object of the journal is the 

 scientific study of morals and religion, it is 

 not likely to become conspicuously a vehicle 

 for the expression of speculation, but will, 

 as " The Index " used to do, make the prac- 

 tical work of improving men's lives and pro- 

 moting the organic growth of society its 

 cbief end, quite irrespective of philosophical 

 or metaphysical doctrine. 



The Chemistry of the Sr/x. By J. Nor- 

 man Lockver, F. R. S. Illustrated. Lon- 

 don : Macmillan & Co. Pp. 457. Price, 

 $4.50. 



The general problem of the chemical 

 constitution of the sun's atmosphere, to 

 which the author has given a large share 

 of his attention for many years, is among 

 the newest and freshest, as well as one of 

 the grandest and most fascinating, ques- 

 tions which science has yet attempted to 

 answer. Although astonishing progress has 

 already been made in this field, consider- 

 ing the difficulties encountered, yet the 

 work is so vast that the time of many ob- 

 servers must be devoted to it before it can 

 be said to be more than begun. The first 

 step in the direction of spectrum analysis 

 was taken by Kepler, who, one hundred and 

 fifty years before Newton, observed the de- 

 composition of white light by the prism. 

 Nothing further was done till Newton took 

 up the subject, and by reasoning and ex- 

 periment greatly enlarged our knowledge 

 of it. Another period of a century and a 

 half elapsed, and then Wollaston discov- 

 ered that the spectrum of sunlight is di- 

 vided into several portions by dark lines. 

 In 1814 and the following years the first 

 great advances in spectrum examination 

 were made. Fraunhofer constructed a map 

 of the solar spectrum, on which he marked 



no less than five hundred and seventy-six 

 dark lines, and these have ever since been 

 known as Fraunhofer lines. His attempts 

 to account for the lines satisfied him that 

 they were not due to any terrestrial cause, 

 but that " they have their origin in the 

 nature of the light of the sun." He intro- 

 duced the use of the telescope for observ- 

 ing the beam of light after its passage 

 through the prism. He also introduced 

 the method of observing stellar spectra 

 which is still employed, and he investi- 

 gated the spectra of artificial light-sources. 

 Sir David Brewster discovered that dark 

 lines were produced in the spectrum when 

 nitrous -acid gas was interposed between 

 the prism and the source of light. Many 

 of these lines seemed to him to be identi- 

 cal in position with some of the Fraunhofer 

 lines in the solar spectrum, and he accord- 

 ingly felt himself justified in announcing 

 the discovery of nitrous -acid gas in the 

 atmosphere of the sun. This was the first 

 chemical touch in solar inquiry. He also 

 stated his belief that all the Fraunhofer 

 lines were due to some absorption at the 

 sun. Foucault then discovered that the 

 bright lines from a colored light had the 

 same places as the dark absorption bands 

 from the same source. In 1852 Professor 

 Stokes first proposed an explanation of 

 this phenomenon, and the same idea was 

 published by Angstrom in the following 

 year. The famous discoveries of Kirch- 

 hoff and Bunsen began to appear in 1859. 

 Among the earliest of these was that the 

 absorber must be cooler than the radiator. 

 Stokes had suggested that the presence 

 of many terrestrial elements might be de- 

 tected in the sun's atmosphere by a com- 

 parison of the spectra of these elements 

 with the Fraunhofer lines, in the way that 

 sodium had already been detected. Kirch- 

 hoff attacked this problem vigorously and 

 obtained abundant results, finding nine ter- 

 restrial metals present in the solar atmos- 

 phere. Angstrom and his collaborator, 

 Thalen, were occupied with similar inqui- 

 ries. 



About this time Mr. Lockyer's work on 

 solar phenomena began, ne applied to the 

 examination of sun-spots and faculaa the 

 device of throwing an image of the sun, or 

 of any desired part of the sun, on the slit 



