176 



as to those beginners who are about to enlist therein, and who 

 wish to know what kind of microscope and apparatus to buy, for 

 they will find in it the unbiased opinion of a first-rate niicroscopist. 



Chapters I. and II. deal with the optics of the microscope, a 

 most important subject, for under the new conditions of things 

 which have arisen during the past twenty years it is impossible 

 for anyone to become a microscopist without some knowledge of 

 the fundamental theories of microscopical optics. An acquaint- 

 ance with these theories is the best safeguard against false inter- 

 pretation of structure. The author has been most judicious in 

 the selection of matter in these two chapters. He has given 

 enough for all practical purposes without going too deep and 

 beyond the scope of the book. 



Passing over the simple, we come to the compound microscope 

 in Chapter IV., of special interest to those about to purchase an 

 instrument. Second and third class instruments only are dealt 

 with, viz., those costing from £1S without objectives to three 

 guineas with two. With almost the whole of the opinions ex- 

 pressed in these chapters we most fully concur ; the only points of 

 divergence would be with regard to the horse-shoe foot and the 

 direct acting screw fine adjustment. As to this last point, any 

 direct acting screw fine adjustment, however well made, will be 

 found too quick for wide-angled objectives when illuminated by 

 large cones ; as regards its durability the new form, as now made 

 by Zeiss, Reichert, and Leitz, is vastly superior to the old model, 

 which was, after a little use, incapable of critically working a 

 student's J-inch objective. 



The latter part of this chapter deals with accessories, including 

 objectives, eye-pieces, and condensers, etc. The reader will find 

 it full of sound advice and practical hints. Chapter V. is full of 

 excellent information on manipulation, but in the next we must 

 notice a slight omission in not pointing out the inversion but non- 

 transposition of an image drawn with a Beale's camera. The fol- 

 lowing chapter is on the preparing and mounting of objects, and 

 the remaining half of the book is devoted to the objects them- 

 selves. With regard to this part we think the selection very 

 appropriate ; a careful study of it ought certainly to whet a student's 

 appetite for more knowledge. The book is written in Mr. Lewis 

 Wright's well-known lucid style, and the figures etc., are all that 

 can be desired. 



