162 SOME NEW FORMS OF MOUNTING. 



heating, just sufficient to loosen it. It can then be turned over 

 and mounted on the cell designed for it. 



The best preparation for fastening the cover to the cell is gela- 

 tine, dissolved in water, with enough alcohol added to liquify it 

 from the jelly state. I place the thin glass on the cell, and then 

 apply the gelatine solution with a brush around the edges, leav- 

 ing the little opening on the lower side. Just enough of the 

 water cement seems to run in under the glass, and to dry just 

 where it is placed. Afterwards the cell may be finished with 

 liquid balsam, carefully avoiding the little aperture, and the 

 outer edge gathered up into a neat trim little circle, with the 

 point of a knife on the turn-table. 



The last and most important recommendation which I have to 

 make, is the strict observance of every rule and precaution tend- 

 ing to neatness and cleanliness. There is a world of beauty and 

 delight in the revelations of the microscope; and there is a 

 peculiar fitness that all the surroundings should be likewise 

 lovely. Whenever I receive a mounted object disfigured with 

 dirt or fibres, with ragged or unfinished settings, I write another 

 name in the already very considerable list of "Exchangers to be 

 avoided." 



