70 ANNUAL OF SCIENTIFIC DISCOVERY. 



the absorption of its silica, so that it attacks the hands of the work- 

 men. 



Mr. Highton produces his solution in the following manner. He 

 uses a soft kind of stone, containing 25 per cent, of silica, found at 

 Farnham, in Surrey, England. This stone readily dissolves in a 

 cold caustic soda solution. 



The solution of soda is placed in the tanks used for steeping the 

 stone, and the Farnham stone is ground and added to the bath. 

 The lime in the artificial blocks removes the silica from the solu- 

 tion, which in its turn takes up more silica from the Farnham stone, 

 and so maintains its supply of silica, thus removing the objections 

 above named. The process is extremely ingenious, and we are 

 informed that flagging, sinks, mantels, coping, cap-stones, sills, 

 etc., are produced by it. Finely cut mouldings are not success- 

 fully produced, and it seems better adapted to a heavier class of 

 work. 



In America also considerable improvement is observable in this 

 field. A Brooklyn paper states that porcelain enamelled bricks are 

 now produced by a firm in that city, of great beauty, both for out- 

 side and inside work, and at a cost not exceeding that of Phila- 

 delphia pressed bricks. Scientific American. 



ARTIFICIAL STONE. THE SOREL PROCESS. 



There is no field of invention which to-day is more replete with 

 general scientific and practical interest than that pertaining to 

 the manufacture of artificial stone. While, in the working of 

 iron, men have sought out means whereby it can be rapidly and 

 cheaply converted into the forms required, the world has, to the 

 present day, been content with working stone after the same gen- 

 eral method used in the construction of the pyramids. The rud- 

 est of all materials is thus changed by immense labor into costly 

 forms ; and the attempts to obviate the necessity for this labor 

 and expense have been confined to a very recent period. 



The idea that stone could be cheaply produced by artificial 

 means, and moulded to any form required, has gradually forced 

 itself upon the minds of modern inventors, and has borne fruit 

 in a large number of processes more or less practical and adapted 

 to secure the end in view. 



Very many of these processes have, however, failed to secure 

 such results as to warrant their general adoption. Some require 

 the steeping of the stones in some solution after they are moulded 

 to remove or transform some contained material, or to add some- 

 thing which could not be advantageously added in earlier stages 



fj d7 v ^5 



of the process. Among these is the celebrated Ransome process, 

 which has not given uniformly satisfactory results. 



Other sorts of artificial stones are sand concretes, made with 

 cements of various degrees of hydraulicity, and many of them 

 of such inferior quality as to render them utterly unreliable for 

 use as building material. 



CJ 



The process invented by M. Sorel, a celebrated French chemist, 

 produces results which we have never seen equalled by any other. 



