TANGY&S LATHE. 



IQ7 



which may be made a very useful tool by the practical 

 microscopist. 



In the grinding operation the student must remember 

 that a polish is not necessary. The Canada balsam in 

 which the section is mounted produces an apparent polish. 



FIG. 183. 



All that is required is to produce a very smooth surface 

 free from scratches, and this is readily done with a brass 

 lap and the finest emery procurable. The one side of the 

 specimen having been brought into the above condition, is 

 to be cleaned and firmly cemented with old balsam to the 

 centre of a 3 x i-inch glass slide. The balsam is dropped 

 upon the centre and warmed over a lamp until, when cold, 

 it is just possible to produce an impression with the nail. 



