•JC.^ THK AMKKICAN MoNTIlLV |S.'|.l., 



A rordial votfoftlianks to Mr. Knicrv tor 11 yciirs service :is cu- 

 rator was moved l)y the president, ami carricil with .i|>|>lause. 



The usual announcements were tlien made and the proceedin<^s 

 terniinateti. The next tirdinarv meetiuL' to be held on Friday, 

 Sej>tonil)er 1'), but the rooms to be oj)en on tiie first and third 

 Kridny evenings in .Inly and August for conversation and exliii)i- 

 tion of specimens. 



NEW ri HLKATIONS. 



T/u'oric (hr Oy)/;.sr/<cn Tn.^frinnrntc narh Ahhc. Von Dr. Siegfried 

 C'zapski. jip. 25)2. Hreslau : Kdward Frewendt, 1S!)3. 

 As would be expected, tliis volume cU-als with the matlii'- 

 matics of oi)tical instrument,^, more (>s[)ecially the construction 

 of leUM's both simple and compovmd. The author has Jiad 

 practical experience in the optical works of Zeiss, in Jena, wliich 

 has prepared him for thepre])aration of tliis most excellent vol- 

 ume on tile science of optical instruments The numerous matiie- 

 matical formula' .are, in many cases, illustrated by drawings- 

 The work is divided into nine chapters or parts. The first deals 

 with geometrical optics, the second with the geometrical theo- 

 ries of optical pictures including a discussion of the various 

 standpoints for the treatment of the (juestion. Then comes the 

 use of light and its character and effect, a discussion of spherical 

 aberration, acromatism, prisms and prism systems. This is 

 followed with an exhaustive discussion, of the princii)al kinds 

 of optical instruments. In fact, all of the principles of optics 

 are brought out and demonstrated mathematically. This ren- 

 ders tiie book of value and it is to l)e regretted that tliere is not 

 an English translation althougli it is presumable that those for 

 whom the book is especially written will find no difficulty in 

 reading the original. The appearance of this volume is a step 

 forward and its effect will undoubtedly be felt in the demand for 

 microscojtes and lenses constructed in the best manner. It will 

 teach the people the i»rinciples emj)loyed in the manufacture of 

 their instruments, which will cause the makers of lenses to put 

 forth their Vjest work. Although the facts stated were for the 

 greater i)art i»ublished, there appears to be no other volume in 

 which all of these important and difficult questions are brought 

 together and explained so satisfactorily as in this one. 



