Septembee 10, I'JO'JJ 



SCIENCE 



341 



Tlie only possible alternative to strict following 

 of rules is that zoologists should agree to accept 

 as final the decision of some authority by them 

 appointed. The vehicle for such authority already 

 exists in the Nomenclature Committee of the In- 

 ternational Zoological Congress, the only body 

 that has any claim to represent either all branches 

 of zoology or all nationalities. 



If I may indicate a convenient form of pro- 

 cedure, I would suggest tliat those zoologists who 

 wish to protect certain names should lay the com- 

 plete facts of the case before the committee, and 

 should accompany their request for the retention 

 of certain definite names in defiance of the rules 

 by the signatures of as many worlcers on the 

 group aflfected as they can obtain. Due announce- 

 ment of the proposed step should be made in cer- 

 tain widely circulated journals and a reasonable 

 time should be allowed for the reception of pro- 

 tests. The committee should ultimately give its 

 decision, and this decision should be published in 

 the aforesaid journals. A summary of the labors 

 of the committee in this direction would of course 

 be given from time to time in the publications of 

 the International Zoological Congress. 



The precise style or mode of appointment of the 

 desired authority does not greatly matter, if only 

 zoologists will agree to accept it. But that it 

 should consist of experts will doubtless be con- 

 ceded. The ruling may be arbitrary, but it must 

 none the less be made with knowledge of all the 

 circumstances of the case and of the results that 

 will follow from it. It must be clearly under- 

 stood that the decision is to be made, not because 

 it is in accordance with the rules, but because it 

 is to produce practical convenience. 



The next steps appear to be, on the one hand, 

 to find out whether a sufficient number of 

 leading zoologists are in favor of these pro- 

 posals; on the other hand, to induce the Inter- 

 national Committee to undertake this added 

 responsibility. 



F. A. Bather 



SCIENTIFIC BOOKS 

 Die hinoTcularen Instrumente, Nach Quellen 

 bearbeitet. Von Moritz von Eohr. Berlin, 

 Verlag von Julius Springer. Pp. 22-3, 1908. 

 This book has been written by one of a 

 small group of men who have grown into 

 prominence by their original work in connec- 

 tion with the optical establishment of Carl 



Zeiss at Jena, where for many years the scien- 

 tific head was Professor E. Abbe. This firm 

 has been known the world over for its high 

 standards ; and in photographic and micro- 

 scopical optics, regarded from both the prac- 

 tical and the purely scientific standpoint. 

 Abbe up to the time of his death was without 

 a peer. His successors, Czapski, Pulfrich and 

 von Eohr have adopted the ideals of their 

 master; and in addition to the details in- 

 volved in directing the scientific work of a 

 large business they have found time to write 

 books that are accepted as important contri- 

 butions to optical science. 



The first part, or theoretic section, of the 

 present volume includes a general introduc- 

 tion, a chapter on monocular vision, and one 

 on binocular vision, in which account is taken 

 of certain limitations that must be heeded, 

 due to the fact that the eye is not a simple 

 instrument but an optical system which dif- 

 fers in some important respects from artificial 

 instruments. This is true, whether the vision 

 is direct or indirect, with one eye or with a 

 pair of eyes used in conjunction with each 

 other. 



The greater part of the book is taken up 

 with the historic development of the subject. 

 The earliest binocular instrument dates back 

 to the beginning of the seventeenth century 

 when Lipperhey, in Holland, constructed the 

 first telescope, and gave to Galileo the starting 

 point for his epoch-making discoveries in as- 

 tronomy. Lipperhey soon constructed a 

 double telescope consisting of a pair of paral- 

 lel tubes, each with convex and concave lens, 

 so that by simultaneous use of both eyes 

 double as much light could be received from 

 the same distant object. There was no con- 

 ception that the images received were in any 

 way different, but the binocular instrument 

 which we call an opera glass, was made prior 

 to 1625, even though not much used. Before 

 the end of that century improvements had 

 been introduced for adaptation to varying 

 interoGular distance, and for focusing to suit 

 the varying distances of objects. 



Aside from the use of the telescope the 

 superiority of a pair of eyes over a single eye 



