IMPROVED MICROSCOPIC APPLIANCES. 61 



1Re\>iew)0. 



BOLTON^S PORTFOLIO.* 



At the moment of going to press, we have received from Mr. 

 Bolton his PortfoUo, No. 7, containing 18 outhne lithographic 

 drawings, with descriptions on the back of each. Five of the 

 subjects relate to the Vegetable, the other thirteen to the Animal 

 Kingdom. We consider it a very good shilling's-worth. 



fIDicroecopical Hpparatue. 



Aperture Diaphragm. 



This apparatus was described at the last meeting of the " Royal 

 Microscopical Society," and was suggested by Mr. Geo. Davis, 

 of Heaton Chapel. It is arranged to fit over the object-glass, 

 and to screw into the body of the Microscope. 



Fig. 6. 



By this appliance, an objective of large angle can be used for 

 objects with depth, and great penetration obtained by simply 

 reducing the diameter of aperture. Its usefulness is still further 

 increased by an adapter for fitting the same under the stage, in 

 place of the ordinary wheel of diaphragms. Mr. Collins, of 157, 

 Gt. Portland Street, London, is the maker. 



* Portfolio of Drawings and description of Living Organisms (Animal and 

 Vegetable), illustrative of Fresh-water and Marine Life, by Thos. Bolton, 

 F.R.M.S., 57, Newhall Street, Birmingham. 



