APPENDIX. Ill 



Infusoires, par D. C. G. Ehrenberg; accompagne de 

 14 Planches J^ A Paris, 1839 : Bailliere, Regent Street, 

 London; price 85. This volume explains the mecha- 

 nism of the best modern microscopes, describes the various 

 modes of examining organic and inorganic subjects, and 

 presents an abstract of Ehrenberg's arrangement and 

 nomenclature of Infusoria. The plates contain 188 un- 

 coloured figures of the principal genera; which, though 

 of very coarse execution, will enable the observer to 

 identify the usual forms. 



Mr. Dancer (13, Cross Street, King Street, Man- 

 chester) supplies a good microscope and the necessary 

 apparatus, in a neat mahogany box, with the highest 

 power magnifying 250 linear, at 11. 155. ; and with an 

 additional power magnifying 400 linear, lOZ. I85. I am 

 informed by Mr. Williamson, surgeon, Manchester, (a 

 gentleman well known for his important microscopical 

 investigations), that these instruments are very excellent, 

 and are the only ones he has employed. 



Objects for the Microscope. — My country readers 

 may find it useful to be informed that objects for ex- 

 amination, both recent and fossil, may be obtained of 

 Mr. Topping, 1, York Place, Pentonville, London. 

 The usual price is Is. 6d. a slide ; but very rare objects., 

 and such as are difficult to prepare, are from 2^. to 3^. 



