364 



widely known in this country than has hitherto been the case. 

 While essentially a book for beginners and written in simple 

 language, it is not by any means of the milk-and-watery type 

 often considered good enough for microscopical babes, for it 

 undoubte-Uy covers a very large portion of the wide field of 

 microscopical manipulation, and does not ignore such subjects 

 as numerical aperture and its determination, under- and over- 

 correction of objectives, centering and focussing of the condenser, 

 etc. About the only serious omission we have noticed is that no 

 mention is made of the use of screens, etc., for the production 

 of monochromatic light for microscopical purposes. The earlier 

 sections of the work deal with the optical properties of lenses, 

 simple and compound microscopes, objectives and eyepieces. The 

 methods of working with the microscope, illumination with the 

 sub-stage condenser, and the drawing of objects next claim 

 attention ; and lastly, there are some useful hints upon the 

 selection and care of a microscope. Nearly every page shows 

 evidence of the practical acquaintance of the author with the 

 subject in hand, and although possibly some experienced workers 

 would take exception to a statement here and there as to the best 

 means of obtaining certain results, there can be no question that, 

 on the whole, we have in the work before us a very reliable intro- 

 duction to the correct handling of a microscope. D. J. S. 



First Steps in Photo-Micrography. By F. Martin Duncan, 

 F.E.H.S. 7 X 4| in., 104 pages, 17 figures. London: 1902, 

 Hazell, Watson and Yiney. Price Is. net. 



It was a good idea of the publishers to include a little work on 

 Photo-micrography in their series of cheap handbooks known as 

 " The Amateur Photographer's Library." It is sincerely to be 

 hoped that the subject will thus be brought before a much wider 

 public than if the book had been issued without such a connecting 

 link to other works on photography. 



Mr. Duncan, in his endeavour to interest those who have not 

 yet taken up the photography of minute objects, very wisely 

 insists in the first place upon the fact that there is considerable 



