468 



In the section devoted to cameras, there is a good illustrated 

 description of a vertical camera for photographing moving objects 

 vvhicli may require the stage of the microscope to be kept in a 

 horizontal position. To a time or instantaneous shutter is 

 adapted a telescopic arrangement for the purpose of watching the 

 object under examination until the desired moment for taking it 

 arrives. 



Tlu' chapters relating to objectives, condensers, illumination, 

 and the actual procedure for making a negative, are all carefully 

 written, and contain much useful information. Very little, 

 however, is said of the use and advantages of light filters or 

 monochromatic illumination, whilst the reader of page 95 might 

 infer that the vertical illuminator is obsolete, the fact being 

 that it is now rapidly attaining to an important position amongst 

 accessories, for by means of it alone can the microscope be applied 

 to the examination of the physical structure of metals and their 

 alloys — a subject, by the way, which is completely ignored in this 

 book. 



A good account is given of chromatic plates, the circumstances 

 under which they should be employed, and the precautions to be 

 observed in order to obtain successful results ; but an opportunity 

 has been missed of giving a description of the methods of photo- 

 graphing objects in their natural colours, especially the Saiiger- 

 Shepherd and Lumi6re processes, by which such beautiful results 

 are now obtained, and which are destined in the future to play 

 an important part in the photography of microscopic objects. 



A favourable recommendation is given to printing-papers of 

 the " Velox " type, which, on account of their remarkably smooth 

 surface, are especially suitable for rendering the fine details 

 required in microscopic work. 



" As an imperfect preparation will never yield a perfect photo- 

 graph," the author devotes the last chapter to giving an outline 

 of the methods which he has found best for the production of 

 good physiological or pathological preparations, also for embedding, 

 section cutting, and making cover-glass preparations. 



A price list and a good index conclude this excellent and cleaily- 

 written book, in which the aim of the author to give practical 

 instruction rather than theoretical information has certainly 

 been attained. A. A. 



