658 REPORT ON NATIONAL 



for mounting, which must be already permeated with the lluid, apply 

 the cover-glass and press out the superfluous fluid. Tress down the 

 cover until the edge comes in contact all around with the fresh shellac, 

 absorbing the liquid that is forced out with blotting-paper. The slide 

 may then be set aside for a few moments, when the cover will be 

 well fixed and the moisture outside will be dried off, or, in case the 

 mounting medium contained glycerine, the slide should be well washed 

 with a stream of water from a wash-bottle. A fresh ring of shellac is 

 then applied to secure the cover-glass and prevent any possible defect 

 in the sealing. The preparation will now keep indefinitely if it is set 

 aside and not handled roughly. 



To insure permanent preservation a mixture of equal parts of gold- 

 size and asphalt varnish or Brunswick black is applied over the shel- 

 lac. One or more coats of this very durable and elastic varnish will 

 protect the more brittle shellac and give a good finish to the mounts. 



A more elegant finish is finally applied, consisting of a single coat of 

 Brunswick black alone. 



Finally, the slide is labeled, and the number on the label is the 

 number of the original specimen in the Museum register. 



