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cooling particles are mixed throughout amass with other gaseous particles, their effectmust principally depend upon the powerthey possess of rapidly abstracting heat fromthe contiguous particles; and this willdepend probably upon two causes, thesimple abstracting power by which theybecome quickly heated, and their capacityfor heat which is great in proportion as theirtemperatures are less raised by this abstrac-tion ,

Whatever be the cause of the differentcooling powers of the different elastic fluidsin preventing inflammation, very simple ex-periments show that they operate uniformlywith respect to the different species of com-bustion, and that those explosive mixtures,or inflammable bodies, which require leastheat for their combustion, require largerquantities of the different gases to preventthe effect, and vice versa; thus one ofchlorine and one of hydrogene still inflamewhen mixed with eighteen times their bulkof oxygene, whereas a mixture of carbu-retted hydrogene and oxygene in the properproportions for combinations, one and two,

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