CALORIFICATION. 359 



weather. The means by which the electric 

 fire is generated on a machine, are evidently to 

 he referred to a mechanical cause ; by the 

 light, which is latent, in the atmosphere, 

 being forced by the motion and pressure of 

 the cylinder, to unite with the opake matter, 

 in the form of an amalgam. 



From the mobility which exists in the parti- 

 cles of which liquid and gaseous bodies, in 

 general, are composed, a more extended sur- 

 face between each presents itself; so that 

 wherever ignition takes place in them it not 

 only extends more widely, but is accomplished 

 more rapidly than in bodies of a more com- 

 pact nature ; instead of slow combustion, ex- 

 plosion ensues. 



The generation of fire takes place by the 

 chemical combination together of hydrogen 

 and oxygen gas ; hydrogen gas is perpetu- 

 ally given out during the decomposition of 

 animal matter, and when there takes place a 

 chemical union of that gas with the oxygen 

 gas which the atmosphere contains, explo- 

 sion immediately ensues, manifesting the phe- 

 nomena of color, and of temperature, the 

 elastic power which these gases separately 

 possessed by combination become weakened 

 and lost ; insomuch, that the water which was 

 either suspended in them, or chemically com- 



