CHEMICAL SCIENCE. 245 



ACTION OF POKOUS BODIES IN INDUCING CHEMICAL COMBINA- 

 TIONS. 



M. B. Corenwinda showed some years ago that partial combination 

 of sulphur and hydrogen may be effected by bringing the two bodies 

 together in the presence of pumice-stone at a red heat. He has re- 

 cently shown that the vapor of water may be also decomposed by sul- 

 phur, when some porous body, at an elevated temperature, is made 

 to intervene. The experiment was conducted as follows : some frag- 

 ments of recently calcined pumice-stone were placed in the middle 

 part of a glass or porcelain tube ; one end of the tube was then filled 

 with pieces of sulphur, a plugget of asbestos being placed between 

 the cork and the sulphur. A tube, by which steam could be sent in, 

 passed through the cork. The pumice-stone was then heated to 

 redness and the sulphur made to slowly volatilize ; at the same time 

 a current of steam was cautiously sent through. After a little time 

 sulphuretted hydrogen was produced in abundance. A still more 

 decided result is obtained if pure calcined silica be substituted for the 

 pumice-stone. The porous body is totally unacted upon in all cases. 



The author directs the attention of geologists to these results ; he 

 thinks that they may explain the presence of sulphuretted hydrogen 

 in certain volcanic emanations. London Pharm. Jour. 



CHEMICAL MANUFACTURES. 



From a report to the British Association (1861) on the chemical 

 manufactures of Lancashire and Manchester, England, we derive the 

 following particulars : 



In the manufacture of sulphuric acid, most of the manufacturers 

 use iron pyrites as a source of sulphur, rather than imported crude sul- 

 phur. The use of platina stills for the rectification of sulphuric acid 

 has now been almost entirely abandoned, and their place supplied 

 by glass retorts, which are made larger and of better quality than 

 formerly. 



The weekly production of sulphuric acid of specific gravity 1.85, 

 in South Lancashire and Manchester, exclusive of what is used in the 

 manufacture of soda ash, is seven hundred tons, or one million four 

 hundred thousand pounds. 



No changes have taken place in the process of manufacturing 

 soda during the last ten years, the essential points of the original 

 method of Leblanc (1798) being still adhered to. The extent of the 

 manufacture has largely increased since the year 1851. The value 

 of alkali made annually in England is two million pounds. The 

 price of oxalic acid, used extensively in calico printing, woollen and 

 silk dyeing, has been reduced by the introduction of a new process 

 for its manufacture, since 1851, from fifteen to sixteen pence per 

 pound to eight or nine pence per pound. The quantity of oxalic acid 

 manufactured at one establishment in Manchester is nine tons (ei i-h- 



\ ^j 



teen thousand pounds) per week. 



The quantity of dye-woods (logwood, fustic, etc.) consumed 

 weekly in the arts in South Lancashire and Manchester amounts to 

 21* 



