772 Transactions of the American Institute. 



The Sorel Artificial Stone. 

 By Dr. Adolph Ott. 



It is characteristic of Portland cement to form with water a stone, 

 similar in composition and physical properties to some of the species 

 of the zeolite family, which we find in various igneous rocks, in sand- 

 stone and metalliferous veins. In that stone, nature is imitated, as it 

 were, but it is very different with the Sorel cement. The stone pro- 

 duced by this cement is not met with in nature, although in strength 

 and hardness it is equalled by few, if any, of nature's rocks. The 

 cement in question is the discovery of Mr. Sorel, in Paris, and is 

 produced by mixing a solution of chloride of magnesium of from 

 fifteen to thirty degrees Baume, in the proper proportions with oxide 

 of magnesium or magnesia. The result obtained is a hydrous basic 

 oxychloride of magnesia. 



That calcined magnesia possesses remarkable hydraulic properties, 

 had already been discovered in 1826 by Macleod, an employe of the 

 East India Company in Madras, by which he had probably been 

 authorized to search for domestic substitutes for the hydraulic mortars 

 of the mother country. 



These experiments were repeated in England with magnesite from 

 Salem, in 1835 ; the results previously obtained were confirmed, and 

 it was furthermore stated that, if the burned magnesite was mixed 

 with sand in the proportion of one to one and a half, it will furnish a 

 stone, adapted for structures of all kinds. In 1836 Vicat stated that 

 pure limestone may be rendered hydraulic by the addition of a sufficient 

 quantity of magnesia. He remarked that the proportion between the 

 burned magnesia and the lime must be from thirty to forty parts of 

 the former to forty parts of the latter. 



In 1847, Pasley in his work, " Observations on Limes, Calcareous 

 Earths, etc.," mentioned that he had also produced a good although 

 slowly setting cement, from previously burned carbonate of magnesia. 

 From these remarks it follows that the discovery of St. Claire Deville, 

 of the hydraulic properties of magnesia, communicated to the Academy 

 of Sciences, in 1865, is not new, as expounded by him and accepted 

 by most chemists. The alleged discovery consists in the fact that a 

 Specimen of magnesia, prepared from the chloride after having been 

 exposed to flowing water for some t'me, had acquired such a degree 

 of hardness" that it would scratch marble, and although subjected to 

 atmospheric action for six years, it underwent no change. The fact, 

 however, was settled conclusively, that magnesia is not near so efficient} 



