MURIATIC ACID BY GALVANISM. 1(\55 



as '4xtradt^(!. "With a lens a iiumber of pyritous pioints may '* 



be observed in it, which by their decomposition and action 



on the schist probably produce an evolution of caloric, that 



heats the water traversing these strata. These being at no 



great depth may have a communication with the atmosphere _ 



through some fissures, and thus the decomposition may have o 



been effected. 



However this may be, it appears to me certain,' that the . 



water must have acquired the heat of 20° [66-2 F.], which 

 is much more than naturally belongs to their depth, by tra- 

 versing these sti-ata. 



I shall here observe too, that, if the heat is to be ascribed pyntes In co»!. 

 to the pyrites, they produce it by their action on the schist, junction with 

 Ifi the observations made at Poullaouen, we found a^onsi- 

 derable quantity of pyrites, without any particular heat 

 being produced : audi must repeat what I have said else- 

 where, that I have seen pyrites extracted, and found the Pyrites do tioI 

 heat not perctptibly greater than in other mines. Accord- always occa- 

 ingly I am inclined to believe, that pyrites in the mass, or 

 at least not radiated, do not prodnre subterranean h^at: but 

 such as are disseminated in extremely small parts through 

 bodies on which sulphuric acid is capable of acting are in a 

 different case, when the atmospheric air can have access to 

 them. In another paper I remarked, that the inflammable air Firedamp not 



called fire-damp in coal-mines does not proceed from the coal Foc^uced by 



. • 1 ^. 1 • 1 • 1 '^"^ most pyn- 



that contams most pyntes, but from that m which scarcely touscoal. 



any is discernible, and where the sulphuret of iron is proba- 

 bly in imperceptible particles. 



XIX. 



Letter from Dr. Veau-de-Launay to J, C. Delametherie, 

 on the Production of oxigejiized muriatic Acid by the gal- 

 vanic Pile*. 



JL FIE experiments with respect to the production of the ^^j^ obtained 

 pxigenized muriatic acid, obtained in distilled water by the by galvanism 



* Journal de Physique, Vol. LXllI, p. 472, Dec. 1806. 



galvanic 



