522 



SCIENCE. 



[N. S. Vol. I. No. 19. 



This is a detail, but it is of prime impor- 

 tance. 



For each subject, as Astronomy, appoint 

 a Director who should be the best man ob- 

 tainable, but who may be any competent 

 and faithful astronomer, even if he is 

 without very wide experience and read- 

 ing. Let each Director go over the author- 

 indexes already in type, and mark each 

 entry there printed with the numerals ex- 

 pressing its class or classes. Many, in fact 

 most, of these papers can be pretty well 

 classified from their titles alone, especially 

 if the subject-index is not too minutely sub- 

 divided. All cases of doubt must be re- 

 solved by a reference to the original memoir. 

 A clerk follows the Director. He finds 

 under Neivconib certain papers which have 

 been marked by the Director as relating to 

 Astronomical Optics — Class XXXII., say. 

 He, therefore, collects these on a card, thus : 



XXXII. 



Neweomh {S): Xos. 1, 11, 19, 26 (vol. I.). 



In a subsequent volume he finds other 

 entries belonging under class XXXII. and 

 under Neweomh, and makes a separate card 

 for them, noting the volume. The same 

 thing is done by the Director for Astronomy 

 for all his classes and for each author ; and 

 by the Directors of other subjects in like 

 manner ; and they are followed by copyists. 

 Finally all cards are sorted into one series : 



First, by the class — as XXXII. 



Second, alphabetically by authors, and 

 then revised and printed thus. 



Class XXXII.— Astronomical Optics — 

 Optics of the Telescope; see also classes 

 XCV., etc., etc. 



Ahhe{C) : Vol. i., 17, 34 ; ii., 80 ; ix., 92, 

 etc. 



Albrecht (T): Vol. vii., 13 ; viii., 31. 



Auivers (A): ii., 7, 23; iii., 18, 37; iv., 

 etc., etc., etc., etc. 



By following out this plan under intelli- 

 gent Directors for the special topics, the 



Koj^al Society would verj- soon have a 

 nearly complete subject-index in one vol- 

 ume, covering its author-indexes, vols, i.-x.; 

 and the plan, once in operation, could be 

 carried on without trouble and at small 

 expense. Such a subject-index would, in 

 my view, supply all real needs in science. 

 It certainljr would in my branch of it. 



The only objection that I can see to this 

 plan is that it is not perfectly complete and 

 logical to the extremest point. If the pref- 

 ace to the proposed book declares that it is 

 not intended to be so, it seems to me that 

 the Eoyal Society need not mind. After the 

 book was printed it would, I think, be used 

 by everyone ; and it would, I believe, meet 

 the wants of every one as nearly as any 

 practicable plan could do. 



If I have extended my remarks too far, 

 I beg you to excuse me. I have desired to 

 show what seems to me to be an easily ob- 

 tained benefit to science, and I trust my 

 suggestion is not impertinent to your in- 

 quiry. I am, My Dear Sir, with high re- 

 gard. Very faithfully yours, 



Edward S. Holden. 



SCIENTIFIC LITER ATUBE. 

 Ein Geologischer Quersehnitt dureh die Ost- 

 Alpen, nebst Anhang iiber die sog. Glarner 

 Doppelfalte von A. Rothpletz, mit 2 

 Tafeln und 115 Abbildungen im Text. 

 Stuttgart. 1894. Pp. 268. 

 This valuable contribution to our knowl- 

 edge of mountain structure is arranged in 

 three parts. The first of these is a state- 

 ment of the petrography and stratigraphy, 

 and the second an account of the tectonic,, 

 of a cross-section of the Alps, in the merid- 

 ian of Munich, from the plain of the Po 

 to the Bavarian plateau, a distance of about 

 230 km. The third part is a discussion of 

 the general results of the author's study. 

 The details of the first two parts are well 

 illusti-ated, both by the fine geologically 

 colored profile on a scale of Tsisst ^^^ ^Y 



