COLLECTION, EXAMINATION, ETC. 



313 



surface allows the whole arrangement to revolve by 

 the mere movement of the finger. When the cover 

 glass has been placed m position the whole can be 

 finished off with paper in the usual way. A neater 

 appearance is obtained by mounting two specimens 

 in each slip, one on either side of the cell.' 



We will now transfer our attention to the 

 methods for mounting Foraminifera as more or less 

 transparent objects in media. After cleaning the 

 material as far as possible, and by the use of liquor 

 potassee, the shells may be immersed in a thin solu- 

 tion of Canada balsam dissolved in turpentine, 



Fig. 42. — Harvey's Method of Mounting 

 Opaque Objects. 



chloroform, ether, or benzole ; this will saturate the 

 tests and expel the air from the chambers. It is by 

 some thought to be expedient to place the vessel 

 containing the shells under an air-pump to complete 

 the process of filling the internal chambers and 

 extracting the air, but this does not in the majority 

 of cases seem necessary. The tests of the Forami- 

 nifera can, after the lapse of a few hours' immer- 

 sion, be mounted in the ordinary way in Canada 

 balsam, using a gentle heat and covering with a thin 

 glass. 



