184 



THE MICROSCOPE. 



from this surface are reflected down on the object "by a 

 piano mirror attached to the object-glass, and on a level 



Fig. 107. — Condenser and Table Gas-lamp. 



with the outer surface. By such means the structure of 

 the scale of the Podura, and the different characters of its 

 inner and outer surfaces, are rendered distinctly visible. 



Lamps. — It is of the utmost importance, both on account 

 of the injury often done to the eyes, as well as for the per- 

 fection of illumination when artificial light is employed, that 

 its quality should be of the whitest and purest kind. The 

 most useful and economical lamp is Collins' Bockett lamp ; 

 it consists of a good paraffin lamp, reflector, and a 2^ 

 condenser, mounted together on a brass-rod stand, which 

 admits of being raised from 9 to 16 inches. The pale blue 

 chimney supplied with it gives whiteness to the flame, 

 and for all the requirements of the microscopist it is de- 



