10 MOUNTING. 



CHAPTER II. 



THE MOUNTING OF OBJECTS. 



THE mounting or " putting up " of microscopic ob- 

 jects signifies their preparation in such way that they 

 may be preserved for future reference and observation. 



As a general rule, objects should be mounted in 

 that manner by which their structure is best and 

 most clearly shown; but in certain instances the 

 objects are mounted so as to make their structure 

 difficult of detection, that they may form test-objects 

 of the power and quality of the microscope. 



Some objects require to be mounted in the dry 

 state, while others are best mounted in liquid ; some 

 again as opake, others as transparent objects : these 

 must be considered separately. 



Dry opake objects were formerly mounted by gum- 

 ming them upon small coin-shaped pieces or disks of 

 cork, blackened upon the surface with a mixture of fine 

 lamp-black and thin warm size, laid on with a hair- 

 pencil. They were kept in a drawer, to the bottom 

 of which a sheet of cork was glued, the disk being 

 transfixed by the pin, so that the free or projecting 

 pointed end of the pin could be thrust into the sheet- 

 cork. This plan may still be adopted in the case of 

 common objects, as seeds, &c. ; but it is objectionable, 

 on account of the facility with which the bare objects 

 are knocked off or injured by dust. 



Hence dry opake objects are usually mounted in 

 such manner as to be enclosed in a cell, the sides 

 being formed by a ring of glass-tube or cork, or a 

 square piece of leather, cardboard, or paper, with a 

 hole cut or punched out of the middle. The glass 

 rings are best ; but as they are expensive, some of the 



