160 SOME NEW FORMS OF MOUNTING. 



subjected to a slowly increasing heat until the cement begins to 

 burn, a very beautiful appearance is given to the under side of 

 the ring, a circle of minute golden links, as seen in the specimens 

 which I offer for your inspection. These rings can then be 

 painted on the turn-table according to one's fancy, and used as 

 cells for any kind of mounting. 



I use this cement, colored with the various aniline dyes which 

 are soluble in alcohol, for painting and finishing slides. These 

 colors are far superior, for all purposes of ornamentation, to any 

 other materials or devices of painting. They dry quickly, and 

 adhere to glass with greater tenacity than any other cements that 

 I have ever used. 



For a cell that will perfectly withstand the action of Canada 

 balsam or turpentine, I make use of shellac cement colored with 

 aniline blue, in the following manner : After a cell of the 

 required depth has been made on the slide, and pretty thoroughly 

 dried in the usual way, it is heated on the heating table, lightly 

 at first, in order to avoid bubbles, then gradually increasing the 

 heat until the cement commences to smoke and the color to burn 

 out. By heating one side of the ring a very little more than the 

 other, as may be done over an alcohol lamp, a part may be left 

 blue, while the rest is yellow or reddish, which has a very pretty 

 effect under Canada balsam. These cells are hard as bone, and 

 can scarcely be cut from the glass. Balsam has no effect on 

 them whatever. Slides may be finished off outside with 

 liquid balsam, made true and circular with the point of a knife 

 on the turn-table. In a few days, or in a shorter time by using 

 the oven, they will be ready to clean and lay away. The cells 

 which I have described are the only cement cells that can be 

 used with Canada balsam. They are particularly adapted to 

 vegetable stainings, algae, and other preparations, either too thick 

 or too tender to be mounted in balsam without something to 

 sustain the thin glass covers. 



In opaque mountings, where cements of any kind are used 

 either for backgrounds or to hold objects in place, I have found 

 it highly advantageous to leave on or in the lower part of the 

 ring, a minute aperture opening into the cell, not necessarily 



