29Q CEMENTS. 



Avitli a spoon until it be reduced to a strong glue, 

 "which does not incorporate with water. Then 

 throw away the hot water; pour cold water over the 

 glue, and knead it afterward in warm water, sub- 

 jecting it to the same process several times. Put 

 the warm glue on a grinding-stone, and knead it 

 with quick-lime until you have a good glue. When 

 you wish to use this glue you must warm it ; if it 

 be employed cold it is not so strong, but it may also 

 be used in that manner. This glue is insoluble in 

 water as soon as it is dry, and it becomes so in 

 forty-eight hours after it has been applied. It may 

 be used for glueing wood, and for cementing marble 

 and broken stone and earthen-ware. Baits for 

 catching fish may also be made of it. Fish are very 

 fond of it, and it resists water. 



Jewellers' Cement 



In setting precious stones, pieces are sometimes 

 broken off by accident. In such cases, they often 

 join the pieces so correctly, that an inexperienced 

 eye cannot discover the stone to have been broken. 

 They employ for this purpose a small piece of gum 

 mastich applied between the fragments, which are 

 previously heated sufficiently to enable them to 

 melt the interposed gum. They are then pressed 

 together, to force out the redimdant quantity of 

 gum. 



Turkey Cement, Jbr jo hung Metals, Glass, ^c. 



Dissolve five or six bits of mastich, as large as 

 peas, in as much spirits of wine as will suffice to 

 render it liquid ; in another vessel dissolve as much 



