INDUSTRIAL PROGRESS DURING THE YEAR 1873. cxxxi 



drochloric-acid gas and air over pieces of clay impregnated 

 with sulphate of copper, and heated to about 400 C. (752'' 

 Fahr.). This method possesses several very advantageous 

 features, and has been introduced into three or four of the 

 largest English works, giving much satisfaction. 



The first of Weldon's processes consisted in passing air 

 into the chloride of manganese solution, with' the addition of 

 milk of lime. In his second method, which is the one alluded 

 to at the outset, magnesia is employed along with the man- 

 ganese, and, from a theoretical stand-point, is a perfect solu- 

 tion of the problem. The following is the process in brief: 

 Hydrochloric acid is allowed to act upon a mixture of mag- 

 nesia and binoxide of manganese, generating chlorine, and 

 leavins: behind a mixture of the chlorides of mao-nesia and 

 manganese. This residue is evaporated to dryness, and heat- 

 ed to a high heat in a current of air, by which treatment the 

 chlorides are decomposed with the liberation of chlorine, and 

 the magnesia and manganese again regenerated, to be treat- 

 ed as before. 



It will be seen from this description that the process is a 

 continuous one, the chlorine being generated by the use of 

 hydrochloric acid and heat alone upon the magnesia and man- 

 ganese mixture. This chlorine is derived from two sources 

 the first portion, formed by the action of the acid upon the 

 magnesia and binoxide of manganese, is pure ; the other, 

 however, which is obtained from the evaporation and roast- 

 ing of the two chlorides, and which forms by far the greater 

 quantity, is diluted with air and nitrogen. Such dilution, 

 for many purposes in the arts, is no disadvantage. It would 

 be of value to know from those who have adopted this in- 

 teresting plan how perfect the regeneration of tlie materials 

 really is inasmuch as the experience in related operations 

 (notably in the continuous j^roduction of oxygen gas) is not 

 of a very encouraging character. 



Among the most interesting and important of the exhibits 

 at the recent Exhibitions at Vienna and London, must be 

 named the various articles fabricated of the new alloy, phos- 

 phor-bronze, which is now attracting much attention on the 

 part of machinists and manufacturers. 



The material in question owes its origin to the discovery 

 some time since made by MM. Montefiore-Levi and Ktinzel, 



