352 (}ri Spontaneous inflammations. 



they use for beer to germinate, dry it in a kiln or stove, ex- 

 cept that destined lor pale beer ; and they generally dry it 

 in a greater or less degree, to give to the beer a colour more 

 cur less dark. It' the grain when taken from the kiln is put 

 warm into sacks, it sometimes, happens that they inflame, 

 and occasiun fires in brew-houses. 



8. Sulphurized and Phosphorized Hydrogen Gas. 



Sahterranean fires and volcaiioes are generally ascribed to 

 the '.i?compu3ition of pyrites and metallic sulphurets buried 

 in the bosom of the earth. These pyritous masses are de- 

 composed by the contact and concurrence of water and air, 

 and the decomposition is ahvavs acconipanicd with a great 

 expansion of caloric, and adisengagementof a highly inflam- 

 mable gas called sulphurised hydrogen gas. This gas in- 

 flames at an elevated temperature, and may communicate 

 inflammation to the sulphur of pyrites, to coals, and other 

 bituminous matters with which they are in general accom- 

 panied. 



Similar inflammations are observed sometimes in the 

 neighbourhood of coal mines. In workmg coal mines, 

 veins and insulated pieces of pyrites are often found : as 

 pyrites always communicates a bad quality to coal, the 

 miners generally lay it aside and take it out of the pit. 

 If these heaps of pyrites, intermixed with coal, are then 

 exposed to the alternate action of the sun and rain, they 

 become heated, and inflame. Great care must therefore 

 be taken that such heaps of pyrites be removed from all 

 Combustible bodies to which they would necessarily com- 

 municate inflammation. There are many operations in na- 

 ture in which sulphurized hydrogen gas is produced ; but it 

 often forms other combinations, according as it is dissolved 

 in v/ater, or is disengaged at a temperature too low to be able 

 to inflame. 



When phosphorus is boiled in a solution of potash or of 

 lime, there is disengaged phosphorized hydrogen gas, which 

 being much more combustible than sulphurized hydrogen 

 gas, inflames at a low temperature as soon as it comes into 

 contact with atmospheric air. This gas, vv^hich in chemical 

 experiments exhibits the beautiful spectacle of a fountain 

 of fire over water, is produced raturally by the putrefaction 

 of animal substances which have been buried. The flames 

 often scon to issue from the earth, and which are known 

 ttnder the name of will-with-the-wisp, arise only from phos- 

 phorized hvdrogen gas : as these fires generally appear in 

 the open fields in places where they arc not in contact with 

 1 dry 



