METHOD OF MOUNTING OBJECTS IN FLUID. 293 



shown by the following figures, will be found the most con- 

 venient, figs. 186, 187, 188, being for the glass slides of one 



Fig. 186. Fig. 187. Fig. 188. 



inch in width, whilst fig. 189 is intended for the slides, which 



Fig. 189. 



are one inch-and-a-half or more in width. These cells are 

 cheaper than those which are drilled in plate-glass, and are 

 quite as neat in appearance. Fig. 190 represents one of this 

 form cemented to a slide and ready for use. 



Fig. 190. 



Drilled Cells. — These are composed of pieces of plate-glass 

 of any convenient size, out of the middle of which either a 

 circular or oval hole has been drilled, the depth of the cell 

 depending in all cases on the thickness of glass used ; when 

 required to be very thick, two or more cells of equal size may 



