A HISTORY OF SCIENCE 



" By experiments with the globe it appeared," wrote 

 Cavendish, "that when inflammable and common air 

 are exploded in a proper proportion, almost all the in- 

 flammable air, and near one-fifth the common air, lose 

 their elasticity and are condensed into dew. And by 

 this experiment it appears that this dew is plain water, 

 and consequently that almost all the inflammable air 

 is turned into pure water. 



" In order to examine the nature of the matter con- 

 densed on firing a mixture of dephlogisticated and in- 

 flammable air, I took a glass globe, holding 8800 grain 

 measures, furnished with a brass cock and an apparatus 

 for firing by electricity. This globe was well exhaust- 

 ed by an air-pump, and then filled with a mixture of 

 inflammable and dephlogisticated air by shutting the 

 cock, fastening the bent glass tube into its mouth, and 

 letting up the end of it into a glass jar inverted into 

 water and containing a mixture of 19,500 grain meas- 

 ures of dephlogisticated air, and 37,000 of inflammable 

 air ; so that, upon opening the cock, some of this mixed 

 air rushed through the bent tube and filled the globe. 

 The cock was then shut and the included air fired by 

 electricity, by means of which almost all of it lost its 

 elasticity (was condensed into water vapors). The cock 

 was then again opened so as to let in more of the same 

 air to supply the place of that destroyed by the ex- 

 plosion, which was again fired, and the operation con- 

 tinued till almost the whole of the mixture was let into 

 the globe and exploded. By this means, though the 

 globe held not more than a sixth part of the mixture, 

 almost the whole of it was exploded therein without 

 any fresh exhaustion of the globe." 



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