WILLIAM GOSSAGE 27 



sand and soda, when it is run out into moulds. 

 When potash is used in place of soda, mixing 

 about equal weights of dry carbonate of potash 

 and clean sand, melting as before. 



The solution of the soluble glass is effected 

 by grinding this to powder and agitating this 

 powder in a pan containing boiling water. 

 The solution is concentrated for use. The 

 viscous solution of soluble glass is applied to 

 the manufacture of certain kinds of soap, by 

 mixing such viscous solution with genuine 

 soap (made from tallow, oil, resin, or other 

 such material), and thereby producing com- 

 pound soaps, possessing valuable detergent 

 properties, independently of the genuine soap 

 contained in such compound soaps." This 

 first invention was followed up by others 

 having a similar purport. It was in April, 

 1857, that the celebrated "mottled soap" 

 patented, which was made by introducing 

 into genuine soap a quantity of solution of 

 silicate of soda and colouring matter, boiling 

 these together until the soap attained such a 

 consistency that when it is put into vessels 

 and allowed to cool slowly the mottling 

 occurs, caused by a semi-crystallisation taking 

 place. The excellent qualities of this mottled 

 soap rapidly gained for it great popularity. 



