MECHANICS AND USEFUL ARTS. 71 



It has for its basis the use of oxychloride of magnesium, a new 

 cement discovered by M. Sorel, who was also the discoverer of 

 oxychloride of zinc. The process has been patented in this 

 countiy, and the patent is owned by the Union Stone Co., of Bos- 

 ton, Mass., who apply it to the manufacture of all kinds of stone 

 moulded in ornamental forms for building purposes. They also 

 apply it to the manufacture of emery-wheels, needle-sharpeners, 

 oil and water stones, soapstone register rings, and faces for sad- 

 irons, etc. In short, they work any kind of stone by this process, 

 first disintegrating it by suitable mills and moulding it again into 

 any form wished, and by the use of the cement named consolidat- 

 ing the mass to even greater strength than it originally pos- 

 sessed, without alteration of color or apparent texture. 



We have now before us specimens of marble, sandstone, blue- 

 stone, etc., which look exactly like the original stone, yet which 

 are even more dense and hard than the stone from which they are 

 made. The marble, which is a beautiful specimen, having a fine 

 crystalline fracture, was made of common marble-yard refuse. 

 In fact, there is no sort of mineral solid material which the mag- 

 nesium cement does not seem capable of uniting, and holding 

 with great tenacity. The process of making stones by this method 

 is as follows: Natural magnesite carbonate of magnesia is 

 first calcined, which reduces it to the oxide of magnesium. In 

 this state it is mixed diy in the proper proportion, by weight, With 

 the powdered marble, quartz, sand, or whatever material forms 

 the basis of the stone. It is then wetted with bittern water, 

 which converts the oxide of magnesium into the oxychloride. 

 The now semi-plastic mixture is rammed into moulds, where it 

 speedily hardens sufficiently to be taken out and laid on skids. 

 In 2 hours' time the stone is so hard that the heaviest rain will 

 not wash the corners off, and in from a w r eek to two weeks the 

 stones may be marketed and used. 



These stones are, according to good authority, capable of with- 

 standing even more severe weather tests than natural stones. 

 Tests made in Boston as to their strength are certified to have 

 given better results than natural stone ; and certainly the speci- 

 mens w r e have, indicate that they are in no way inferior to the 

 natural stones they severally represent. 



The hydraulicity of magnesium salts has attracted the attention 

 of several of the most eminent chemists in the world. 



In a note recently read before the Academy of Sciences, in 

 Paris, by M. Deville, he called attention to the action of water 

 upon magnesia. A portion of a specimen of magnesia, prepared 

 by calcining the chloride sent him several years previously by 

 M. Denny, was kept constantly exposed to water under the taps 

 of his laboratory. After a time it assumed a remarkable con- 

 sistence, it could scratch marble, and, though subjected to atmos- 

 pheric action for 6 years, it underwent no perceptible change. 



The substance proved to be a crystallized hydrate. Subse- 

 quently, with magnesia prepared from the hydrate, he obtained 

 similar results, and casts of medals after having been placed in 

 water assumed the appearance of marble. 



