CEMENTS AND VARNISHES. 251 



made by E. Ward, Oxford Road, Manchester. Its best sol- 

 vent is a mixture of wood-naphtha and alcohol. RonssBLET 

 considers it the best shellac varnish he has met with, better 

 than Bell's. 



464. Bell's Cement— Composition unknown. May be ob- 

 tained from the opticians, or from J. Bell & Co., chemists, 

 338, Oxford Street, London. This varnish sets quickly. 

 The cover should be ringed with glycerin jelly before apply- 

 ing the varnish, especially with glycerin. It is soluble in 

 ether or chloroform. It is not attacked by oil of cedar. 



465. Miller's Caoutchouc Cement. — Composition unknown. 

 May be obtained from the opticians. A very tenacious and 

 quickly drying cement. It may be diluted by a mixture of 

 equal parts of chloroform and strong alcohol (see Rousselet, 

 Journ. Queh. Cluh., v, ii, 1895, p. 8). 



466. Clarke's Spirit-proof Cement. — Mr. Cu. Rousselet has 

 highly recommended this to me. It may be procured from 

 Mr. J. Bolton, 25, Balsliall Heath Road, Birmingham. 



Rousselet finds it the best he has tried for alcoholic 

 liquids, but not perfectly proof against watery media. 



467. Asphalt Varnish {Bitume de Judee). — Unquestionably 

 one of the best of these media, either as a cement or a varnish, 

 •provided ,it he procured of good qualify. It can be procured 

 from the opticians. 



468. Brunswick Black. — See early editio7is, or Heaim, How to 

 Work, etc., p. 49. 



469. Gold-Size. — Best obtained from the opticians. It is 

 soluble in oil of turpentine. A good cement, when of good 

 quality, and very useful for turning cells. 



470. Marine;^61ue. — Found in commerce. Caepenter says 

 the best is that known as Gr K 4. Best obtained from the 

 opticians. It is soluble in ether, naphtha, or solution of 

 potash. Its use is for attaching glass cells to slides, and for 



