Additional N'oles. 387 



lion ©f which explosion is produced, ntid light and heat are 

 liberated. 



Dr. Gibbes also adopts a chc-inicil theory of electricity. He 

 supposes that oxygen gas is pn^duced by the union of positive 

 electricity with water; and hydrogen gas by the union of negntiic 

 electricity with water ; and that water, uniting in dift'ercnt pro- 

 portions with the two electricities, is the ponderable part of all the 

 elastic fluids. He asserts that, by the positive electricity, metals 

 are oxydated, and blue vegetable colours reddened ; and also that 

 the acidifying effect of electric commotions in the atmosphere, on 

 weak fermented liquors, is unquestionable. On the otlicr hand, 

 according to this writer^ by negative electricity the vegetable blue is 

 restored, and the oxydated metal revived. 



These circumstances, among others, lead Dr. Gibbes to con- 

 clude, that when hydrogen gas is produced by the affusion of 

 water on red-hot metal, and the metal is at the same time oxy- 

 dated, a decomposition of j?re ratlier than ofii:ater has taken place -, 

 that the hot nietal has parted with negative electricity, which, 

 uniting with a small proportion of the water, has formed hydrogen 

 gas ; (hat a greater proportion of the water has united with ihe 

 positiv'e electricity, and entered, as oxygen gas, into combination 

 with the metal. When the two gasses are inflamed together 

 the spark attracts to itself, in due proportions, the two electrici- 

 ties contained in the two gasses, which unite with explosion, 

 and produce fire. The water with which they were before com- 

 bined is of course deposited. 



The reason why inflammable substances bum in oxygen gas, 

 and not in hydrogen. Dr. Gibbes supposes to be that negative elec- 

 tricity greatly prevails in all inflammable substances. Neither of 

 the gasses can be inflamed separately, because fire depends on the 

 union of the two electricities ; and such union cannot be eflected 

 unless both are present in due proportion. 



Dr. Gibbes supposes that the further illustration of the effects 

 of the two electricities as chemical agents will set aside some of 

 the leading doctrines of the Lavoisierian theory, and aftbrd an easy 

 solution of certain phenomena which that theory cannot explain. 



It is a curious fact tliat Dr. Gibbes, in supposing that oxyi^cn ga« 

 is produced by the union of positive electricity with water, and that 

 hydrogen gas is produced by the union of negative electricity with 

 water, was anticipated by Dr. Priesiley.— Scu his Letter to 1): 

 Woodhouse, Sept. iG, 1901, in the Medical Rcp-^iitory, New 

 York, vol. v, p. loS. 



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