8 ARGON, A NEW CONSTITUENT OF THE ATMOSPHERE. 



Attempts to repeat Caveiulish's experiment in Cavendisirs manner have only 

 iiKMeast'd tlii' admiration with which we regard this wonderful investisjation. 

 \\'orking mi almost microscopical (piantities of material and by operations extend- 

 ing over days and weeks, he thus established one of the most important facts in 

 chemistry. And what is still more to the purpose, he I'aises as distinctly as we 

 could do, and to a certain extent resolves, the question above suggested. The pass- 

 age is so im])ortant that it will be desirable to quote it at full length : 



" As far as the experiments liithei'to published extend, we scarcely know moie 

 of the phlogisticated part of our atmosphere, than tiiat it is not diminished by 

 lime-water, caustic alkalies, or nitrous aii; that it is unfit to supi)ort fire, or main- 

 tain lift' in animals; and that its S[)ecific gravity is iii>t miicli less than that of 

 coruraon air; so that, though the nitrous acid, by being united to phlogiston, is 

 converted into air possessed of these properties, and consetpiently, though it was 

 reasonable to suppose, that part at least of the phlogisticated air of the atmosphere 

 consists of this acid united to phlogiston, yet it was fairly to be doubted whether 

 the loliole is of this kind, or whether there are not in reality many ditfeient sub- 

 stances confounded together by us under the name of phlogisticated air. 1 there- 

 fore made an experiment to determine w hether the whole of a given portion of the 

 phlogisticated air of the atmosphere could be reduced tt> nitrous acid, or whether 

 there was not a pait d' a different nature to the rest, wliicli would i-efuse to undergo 

 that change. The foregoing experiments indeed in some measui'e decided this 

 jioint, as much as the greatest part of the air let up into the tube lost its elasticity ; 

 yet as some remained unabsorbed it did not ap[)eai' for certain whether that was of 

 the same nature as the I'est or not. For tiiis pur[>ose I diminished a similar mix- 

 ture of dephlogisticated and conunon air, in the same manner as Ijefore, till it wjxs 

 reduced to a small pait of its original bulk. I then, in order to decompound as 

 nnuli as I could of the phlogisticated air which remained in the tube, added some 

 dephlostigated ail' to it and ci>nlimiecl the spark until iio I'm tin r diniiniilioM took 

 place. Having b\' tliese iiie.Miis coiideMsed as miicli as I could o|' ilie phlogisticated 

 air, I let up some solution of li\ei' of .sulphur to absorb the dephlogisticated air ; 

 after wiiich only a small bubljle of air remained unabsorbed, which certainly was 

 not more than -j-J^- of the bidk of the )>hlogisticated air let up into the tube; so 

 that if there is any part of the phlogisticated air of our atmosphere which differs 

 from the rest, and cannot be reduced to nitrous acid, we may safely conclude that 

 it is not more than -^-^ part of the whole." 



Although Cavendish was satisfied with his result, and does not decide whether 

 the small residue was genuine, our expeiiments about to be related render it not 



