CEMENTS AND VARNISHES. 293 



St. Petersburg; or 79, Gaclen, Vienna; or 1, Eomerthal, 

 Mayence. 



471. Shellac Varnish (BEALE, p. 28). Shellac should be broken into 

 small pieces, placed in a bottle with spirit of wine, and frequently shaken 

 until a thick solution is obtained. The Micro. Dictionary says that the 

 addition of 20 drops of castor oil to the ounce is an improvement. 



Untrustworthy, but useful for protecting balsam mounts from the action 

 of oil of cedar. 



472. Sealing- Wax Varnish (Micro. Diet., " Cements "). Add enough 

 spirit of wine to cover coarsely powdered sealing-wax, and digest at a gentle 

 heat. This should only be used as a varnish, never as a cement, as it is apt 

 to become brittle and to lose its hold upon glass after a time. 



473. Tolu Balsam Cement (CARNOY'S Biol. Cell., p. 129). 



Tolu balsam . . .2 parts. 



Canada balsam . . . .1 part. 



Saturated solution of shellac in 



chloroform .... 2 parts. 

 Add enough chloroform to bring the mixtur<= to a syrupy 

 consistence. CAKNOY finds this cement superior to all others. 



474. Other Cements and Varnishes. See previous editions. 



