LITERARY NOTICES. 



2 43 



proving many processes of manufacture, 

 and as an aid in almost every branch of 

 scientific inquiry, became each year more 

 clearly recognized. We have seen Sorby 

 analyzing by its means the coloring-matter 

 of plants, and the entomologist comparing 

 the spectrum of the glow-worm and the 

 fire-fly, or discussing the absorption-bands 

 peculiar to the fluids of insects. The mi- 

 croscopist employs the powers ot the new 

 analysis to solve problems which the mag- 

 nifying powers of his instruments would be 

 altogether unable to cope with. Nothing, 

 in fine, seems too vast or too minute, too 

 distant or too near at hand, for this won- 

 derful instrument of research, which deals 

 as readily with the mass of Sinus, a thou- 

 sand times larger and a million times farther 

 away than our sun, as with the ten-thou- 

 sandth part of a grain of matter in a flame 

 within a few inches of the spectroscopic tube. 

 It is, perhaps, not the least wonderful 

 circumstance about the new analysis that it 

 has already been made the subject of many 

 volumes of scientific lore. A goodly libra- 

 ry might be filled with the printed matter 

 which has been devoted to spectroscopic 

 analysis, either in works definitely directed 

 to the subject, or else in chapters set apart 

 for its treatment in works on other subjects. 

 But the general public has undoubtedly not 

 had occasion to complain, as yet, that the 

 analysis has been too fully expounded to 

 them. It cannot be denied, indeed, that 

 hitherto the vaguest possible ideas have 

 been entertained by many respecting the 

 most powerful mode of scientific research 

 yet devised by man. The work of the tele- 

 scope or of the microscope all men can at 

 once understand, even though the principles 

 on which these instruments are constructed 

 may not be thoroughly understood save by 

 a few. But the case is very different with 

 the work of the spectroscope. When the 

 astronomer says that with a telescope mag- 

 nifying so many times he can see such and 

 such features in Mars or Venus or Jupiter, 

 every one knows what he means ; but, when 

 the spectroscopist says that his instrument 

 shows certain bright lines in the spectrum 

 of a nebula, or certain dark lines in the 

 spectrum of a planet, the general reader has 

 to accept on trust the interpretation placed 

 on such results by the observer. 



It was to remove this difficulty that the 

 present volume was originally written. Of 

 its value in this respect we can have no 

 higher evidence than the fact that Dr. Hug- 

 gins named it to the two ladies who have 

 translated the present edition as ' the best 

 elementary work on spectrum analysis.' 

 The translators the Misses Lassell (daugh- 

 ters of the eminent astronomer who has just 

 vacated the presidential chair of the Astro- 

 nomical Society) remark that the interest 

 they derived from the perusal of this work 

 'suggested the idea of undertaking its 

 translation.' Dr. Huggins agreed to edit 

 the volume ; and, accordingly, we find ap- 

 pended to the valuable text of Dr. Schellen 

 many important (in some cases absolutely 

 indispensable) notes by the English master 

 of the subject. 



The work thus translated is from the 

 second German edition, which is not only 

 much larger than the first, but is improved 

 by the correction or omission of several 

 faulty passages. It consists of three parts. 

 The first describes the various artificial 

 sources of high degrees of heat and light. 

 The second relates to the application of the 

 analysis to terrestrial substances. These 

 portions of the work are extremely impor- 

 tant, and, on the whole, they are well ar- 

 ranged ; but, to say the truth, they are rather 

 dry. Fortunately for the general reader, 

 they occupy together little more than one- 

 third part of the work, the remainder being 

 occupied by the description of the applica- 

 tion of spectrum analysis to the heavenly 

 bodies. In this, the third section of the 

 book, we have four hundred pages full of 

 the most interesting matter. The investiga- 

 tions of astronomers into the nature of the 

 sun's globe, and of those wonderful enve- 

 lopes which surround him, are described 

 with great fulness of detail, and illustrated 

 by a fine series of drawings. The colored 

 plates, representing the prominences as seen 

 by Zollner, Respighi, and Young, are espe- 

 cially interesting and suggestive, more par- 

 ticularly when the reader's attention has been 

 directed to the scale of miles or rather of 

 thousands of miles placed under each. 

 Respighi, indeed, rejects mile-measurement 

 altogether, and can be satisfied only by a 

 scale of terrestrial diameters ; so that, in- 

 stead of showing how many thousands of 



