iliij|UAu*i 



Kg. 176. 



METHOD OF MOUNTING OBJECTS IN FLUID. 285 



from running in to spoil the object, the author's late brother, 

 Mr. Edwin Quekett, adopted the plan represented by fig. 176, 

 which was to take a piece of writing paper, about one-eighth 



of an inch smaller 



' " ■■ "l^""nr'"=" 1 ■ ,. each way than the 



cover to be em- 

 ployed, and from 

 the middle of this 

 to cut a square or 

 circular hole suf- 

 ficiently large to 

 hold the object. After the fluid had been placed on the slide, 

 and the object deposited in it, this paper cell was also placed 

 in the fluid, and when adjusted to the centre of the slide, the 

 cover was laid on in the usual manner, the paper preventing 

 the cement from running beyond it to obscure the object. 

 Following out this principle, Mr. Darker has ingeniously con- 

 trived a cell of the form represented in plan by A B, fig. 177, 

 and in section by C. These cells are cast in glass of the size 



represented by A B, and, 

 in order to prevent the 

 cement from running in, 

 the sides are constructed 

 as shown by G D B ; B 

 being the outer margin of 

 the cell, D a flat surface 

 for the cover to rest on, 

 and G a gi'oove between it and the inner margin. These cells 

 are cemented to the shdes in the usual manner, either with 

 marine-glue or asphaltum dissolved in turpentine, the method 

 of cementing down the cover is the same as in the other forms, 

 a small quantity of gold-size being applied around its edge 

 either with a brush or the finger before it is placed on the fluid 

 within the cell ; should there be any tendency in the cement 

 to run under the cover, it must first fill up the groove before 

 it can get into the cavity where the object is. The under 

 surface of this form of ceU can be ground sufficiently thin to 

 enable a quarter of an inch object-glass to view any object; 

 contained within it. 



Fig. 177. 



