302 CEMENTS. 



Another Cement that will stand the Actio?! of Boiling 

 Water and Steam. 



This cement, which is preferable even to the 

 former for steam-engines, is prepared as follows. 



Take two ounces of sal ammoniac, one ounce 

 of flowers of sulphur, and sixteen ounces of cast 

 iron filings or borings. Mix all well together by 

 rubbing them in a mortar, and keep the powder 

 dry. 



When the cement is wanted for use, take one 

 part of the above powder and twenty parts of 

 clean iron borings or filings, and blend them inti- 

 mately by grinding them in a mortar. Wet the 

 compound with water, and when brought to a con- 

 venient consistence, apply it to the joints with a 

 wooden or blunt iron spatula. 



By a play of affinities, which those who are at 

 all acquainted with chemistry will be at no loss 

 io comprehend, a degree of action and re-action 

 takes place among the ingredients, and between 

 them and the iron surfaces, which at last causes 

 the whole to unite as one mass. In fact, after a 

 time, the mixture and the surfaces of the fianches 

 become a species of pyrites, holding a very large 

 proportion of iron, all the parts of which cohere 

 strongly together. 



Blood Cement. 



A cement often used by copper-smiths to lay 

 over the rivets and edges of the sheets of copper 

 in large boilers, to serve as an additional security 

 to the joinings, and to secure cocks, &c. from 

 leaking, is made by mixing pounded quick-lime 



