IS07,] Component Parts of Atmospheric Air. 



543 



ccrtained that 100 parts, in hulk, of oxy- 

 gen gas require nearly 200 parts of hy- 

 drogen, to fatunite it completely. Ac- 

 cording to the experiments of Fourcroy 

 and Sej^uin, 100 parts of the formci- re- 

 ■quire 205 of the latter. 



Their objedt was now to afcertain, 

 ■vvhat were the proportions of tiiefe two 

 galfcs in the water. From the experi- 

 ments of Fourcroy, Vauquelin, and Se- 

 guin, the molt accurate hitherto made on. 

 jhe I'ubjeCt in quelHon; water contains in 

 weight o5,C62 parts of oxygen, and 

 l4,o38 of hydrogen. &\l thefc experi- 

 ments having been made at the tenipera- 

 tvire of 14°, and no aUowaucc made for 

 the water held in folution by the gas, it 

 follows, if we admit with Saufl'ure, that a 

 taibic foot of air, at the temperature of 

 14°, contains nearly 10 grains of water in 

 folution, tliat the relative weight of the 

 oxygen to die hydrogen, in place of being 

 85,662 to 14,338, ihowld iiave been 

 Sr,41 to 12,59, 



Having afcertained the accuracy of 

 Volta's eudiometer, they proceeded by 

 its means to fix the precife quantity of 

 oxygen contained in atmofpheric air ; 

 and the refult of thcfc experiments is, 

 that it contains 0,21 parts of oxygen. 



Not having been able to difcover any 

 fenfible quantity of hydrogen in this at- 

 iTiofpheric air, they are of opinion, if any 

 ■was prelent, it could not exceed OjOO.') ; 

 for it is plain that the hydrogen, which is 

 jconltantiy difengaged from ditfercnt bu- 

 /Jics, mult be dilcovcrable, unlets when it 

 «loes not amount to onc-thoufiuidth part. 

 Carbonic acid mull likewife he prelont 

 in atmofpheric air, though Humboldt w as 

 not abie to difcover it ; a circumiiance 

 which icvide^itly p^o^■es that it cxifls 

 tlierein only isx a very minute proportion. 

 Our dieiuifts next afcertained that the 

 })urity of atmofpheric airj varies very lit- 

 tle ill different htuations. They tilled a 

 vell'cl with air in the pit in the Thatlre- 

 Frun^ok, when it was extremely crowd- 

 ed, and another at the upper part of the 

 liouiie. The air contained in tlicic vefl'els 

 fcarcely rendered lime-water turbid. 

 Common atmofpheric air contains 



of oxygen - - - - 0, 210 

 Tliat taken at the upper part of 



the T/icatre-Frun^ois - - 0, 202 

 Tliat taken in the prt - - - 0, 204 

 Seguin alio analyzed the air in the 

 wards of hufpitals, which were kept care- 

 fully lliut, during twelve liours prcviousto 

 tilt ex[)erimcnts. This air had acquired 

 sin infjpporlable fetid odour, notwith- 

 (tanding which, he found it, on examina- 

 tion, iitiirly us pure us couiuioii atino- 



fpheric air. Fontana had lioforc that pe- 

 riod obtained the fame reiults in the llo~ 

 tti-Dleu, at Paris. From tlu fe facts, it 

 Ihould fecin, that the incomcniences ex- 

 perienced in crowded apartments, cannot 

 be attributed to a deficiency of oxygen, 

 but mult proceed li-om particular pellilen- 

 tial emanations. 



Water, it Jias long been known, con- 

 tains air, as air, in like manner, contains 

 water. Alter the moft accurate exami- 

 nation of the air difengaged from water, 

 Humboldt and Gay-Luffac afcertained, 

 ill the moll fatisfattory manner, that it 

 contains more oxygen in a given quan- 

 tity than atmofpheric air; but this por- 

 tion varies according to the period at 

 w hich it is collected. 

 Thus, air extricated from water 

 when it begins to be heated, 

 contains of oxygen - - 0, 33. T 

 When farther heated - - 0, 27. 4 

 When Hill farther heated - - 0, 30. 2 

 When at the boiling point - 0, 32. 5 



Seiiebier, Ingenhouz, Berger, and De- 

 lametherio, had previoully proved, by 

 numerous experiments, that water ab- 

 forbcd the different gales wliich changed 

 their quality. Thefe experiments, on 

 being repeated by Humboldt and Gay- 

 Lulfac, furniihed the following refults. 



One hundred and nine parts of oxygen 

 gas expofcd to the attion of the water of 

 the Seine, were reduced 40 parts; the re- 

 mainder examined by the eudiometer, 

 was found to contain 37 parts of azote, 

 'i'hus it had loll 77 of oxygen ; aiKl 37 

 parts of azote, according to them, were 

 difengaged from the water. 



One hundred parts of hydrogen, «x- 

 pofed in like manner, loft 5 partsi' Tlie 

 want of anil'onnity iu the refults which 

 they obfaiued, prevented them from de- 

 ciding on the changes whicii the gas un- 

 dcrueiu during its expofure. 



One hundred parts of azote, expofed to 

 the action of water, were diminiflied 

 three hundredths. The reliduc coiitain- 

 ' ed 11 parts of oxygen diljilaced, in the 

 opinion of Humboldt and Gay-Luflac, by 

 14 parts of azote. 



Two hundred parts of hydrogen, mixed 

 with 400 parts of oxygen, and expofed tp 

 the contact of Seine water, during ten 

 davs, were diminiflied 38 parts; but the 

 rclidue contained 142 of hydrogeft, 174 

 of oxygen, and 246 of azote. 



Tliele experiments are all in perferb 

 conformity with thofe previoully made by 

 Delamctherie, Ingenhou/^ A'C. ijut tlw 

 coiiciulions drawn from thein by Hum- 

 boldt, and Gay-Lulfac, are extremely 

 diiicrcnt. . 



Z Z 3 Dclu^ 



