l886.] NEW-YORK MICROSCOPICAL SOCIETY. 27 



geous to buy the varnishes ready made, and then proceed as 

 follows : — 



Taking equal parts of the best, clearest, and hardest amber- 

 varnish and copal- varnish, mix them and heat until all the tur- 

 pentine has disappeared. This will require a temperature of 

 ioo° to 150° R. As soon as all the turpentine has evaporated, 

 remove the dish from the flame, allov/ it to cool somewhat, and 

 then add oil of lavender to the liquid in the proportion of i to i ; 

 mix well, and allow the entire mass to cool thoroughly. The 

 process is terminated by adding from 20^ to 40^ of artificial 

 cinnabar (eosin with cinnabar), which should be very carefully 

 and thoroughly rubbed in. The best method for rubbing in the 

 cinnabar is that employed in the preparation of fine oil-paints. 

 Should the cement when finished be too thick for use, as much 

 oil of lavender as will give the required fluidity may be added. 

 The component parts and their proportions would then be as 

 follows : — 



Amber, - - - - 25 parts 

 Copal, - - - - 25 " 

 Linseed-oil varnish, - - 50 

 Oil of lavender, - - 50-60 " 

 Artificial cinnabar, - - 40-60 " 



Dr. Heydenreich continues his article by describing the 

 manner in which the cement should be applied, but as his 

 method is the same as that employed in the use of Canada 

 balsam and other cover-glass cements, and, consequently, 

 familiar to all microscopists, I have not thought it necessary to 

 make a note of it. I will, however, state that he advises, in order 

 to secure a perfect mount, that a second ring be made after the 

 first or second week from the time of mounting ; and a third, 

 after the first or second month ; each additional ring to be 

 slightly wider than the preceding one. 



