W. Skey. — Formation and Constitution of Torbanite. 387 



evolved, the mineral loses the whole of it, even at common temperatures. 

 Now, I conceive water has relations to the so-termed hygroscopic substances, 

 similar to those ammonia sustains to argentic chloride ; it chemically combines 

 with these substances, and the compounds thus formed are not permanent 



vapour 



than that at which they were produced. 



Lastly, as to a production of heat by the chemical combination of water 

 with the substances of plants, a combination brought about by changes 

 in the temperature of the air, or in the tension of its vapour, this is no doubt 



;han 



affecting the vegetable world abruptly.* 



Art. LXII. 



Minerals. By William Skey, Analyist 



of Torbanite and 



of New Zealand. 



[Read before the Wellington Philosophical Society, 29th August, 1874.] 



In prosecuting experiments, previously detailed, upon the evolution of heat 

 caused by mixing dry clay with various liquids, I noticed such an increase of 

 temperature in the case of petroleum that I suspected an absorption of a 

 portion of the matters dissolved in this liquid had occurred, and so was led to 

 investigate the matter further, when the following results were obtained : 



(1.) That our commercial kerosenes are nearly or quite decolorised by 



best 



modified. 



(2.) That this process is very much quicker when the clay used has been 

 dried at 100° or so C. 



(3.) That in such a case the clay, if white, acquires a rose and afterwards 



a black colour, while its streak is light brown. 

 (4.) That torbanite has the same effect as clay. 

 (5.) That the coals I have examined, whether hydrous or anhydrous do 



not appear to exercise any absorbent action upon the petroleum oils. 

 (6.) That the same is true of diatomaceous earth (dry), carbonate of lime, 



and gypsum, hydrous or anhydrous, also pumice-stone and pipe-clay 



(ignited). 



been 



heated to 100° to 150° C, blackens clay, but has no such effect upon 

 other porous substances, as gypsum, or prepared silica. 



As 



rous wool, it is probable that we have in this a provision of the same nature 

 animal world too.— W. S.. 23rd Anril. 1875. 



