HISTORY OF THE ATOMIC THEORY. 1 ^^ 



sulphur, exclusive of water. One hundred and forty-three 

 grains of dephlogisticated air contain 41 of water, for lime 

 will abstract 26 grains from it, and the remainder cannot be 

 separated from it in its aerial state; therefore 100 grains 

 of sulphur, making an allowance for water, require 100 or 

 102 of the real gravitating matter of dephlogisticated air 

 to form volatile vitriolic acid ; and as volatile vitriolic acid 

 is very little short of double the specific gravity of 

 dephlogisticated air, we may conclude that the ultimate 

 particles of sulphur and dephlogisticated air contain equal 

 quantities of solid matter ; for dephlogisticated air suffers 

 no considerable contraction by uniting to sulphur in the 

 proportion merely necessary for the formation of volatile 

 vitriolic acid. Hence we may conclude, that, in volatile 

 vitriolic acid, a single ultimate particle of sulphur is inti- 

 mately united only to a single particle of dephlogisticated 

 air ; and that, in perfect vitriolic acid, every single particle of 

 sulphur is united to two of dephlogisticated air, being the 

 quantity necessary to saturation." 



** As two cubic inches of light inflammable air require but 

 one of dephlogisticated air to condense them, we must suppose 

 that they contain equal number of divisions, and that the 

 difference of their specific gravity depends chiefly on the size 

 of their ultimate particles; or we must suppose that the 

 ultimate particles of light inflammable air require two or 

 three, or more, of dephlogisticated air to saturate them. 

 If this latter were the case, toe might produce water in an 

 intermediate state, as well as the vitriolic or the nitrous 

 acid, which appears to be impossible ; for in whatever pro- 

 portion we mix our airs, or under whatsoever circumstance 

 we combine them, the result is invariably the same. This 

 likewise may be observed with respect to the decomposition 

 of matter. Hence we may justly conclude, that water is 

 composed of molicules formed by the union of a single ulti- 

 mate particle of dephlogisticated air to an ultimate particle of 



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