146 SUPPOSED CHEMICAL AFFINITY OF 



acquaintance with authorities, may fairly, it is prefumed, be 

 deemed the moft cogent that have been offered on that fide of 

 thequeftion. It is the objeft of this communication to fliew 

 their infufficiency. 

 J. The conftant 1. The conflant proportion of azol and oxigen in llie atmo- 

 proportion of fpliere is confidered as an argument for their being held by affi- 



oxigen andazot c • j j -^ l ^ •. - u ■ c c i 



fupoofed to be "'0'* ^° indeed it may ; but it is equally in favour oi my hy- 



jeguhted by af- pothefis, and therefore nothing tending to decide the quefrion 



ereafi-d aitraSlion^'^^'^ ^^ obtained from it. For, let part of the oxigen be ab- 



of the abundant ftra(5ed any where from the atmofphere; then the azot may be 



^^^' fuppofed to attract the oxigen from the vicinity, and thus the 



equilibrium be reftored : but it is certainly equally fatisfadtory 



tofuppofe that the oxigen in the vicinity, meeting, with a lefs 



repulfive power from the deficient quarter, nothing"prevents 



its diffulion into that quarter but the azot previoully there, 



which, by hypothefis, can only retard, but by no means j9rere«^ 



-..-but this may the ef]e(5t. Thus then, whether the azot attruSi the oxigen, or 



with more pro- the oxigen j'epe/ itfelf, the effect is precifely the fame. From 



cribed to (f/wi- this faft fimpiy, it is impoffible therefore to decide the merits 



tninifoedrepul- Qf either theory; but if it be found tha-t any one gas diOlifes 



jfurt of the dc- . . ■ 1 .1 r i • • -ii i 



ficientgas: For, ''i*^'' '" ^'''^ Other, With nearly the lame celerity, jt will be a 

 &c. prefumption in favour of my hypolheiis; if otherwife, it may 



be urged that the quicker diffufion is owing to the ftronger afFi- 

 nity, I have made a great number of experiments on this head, 

 but could not find any remarkable difFerence in the time and 

 circumftances of diffufion of the fame gas, 

 2. Humboldt and 2. It is faid the experiments of Morozzo and Humboldt fliew 



Morozzo s ex- ^j^^j. ^-j. poQ-^^d-es different properties from a mere mixture of its 

 periments ; Ihat ' ' ' .... 



a mere mixture two component parts. I do not credit the experiments. — 

 of the safes dif- Humboldt finck a variable quantity of oxigen, from 2.5 to 30, 



fcrs from atm. ... , , , 



air: not ere- o"" more per cent, in the air ; whereas others who are more 



ti'ted. accurate, find but 21, or at moft 22, and that fO)?/?a/;^. It is 



no wonder then, if ht*mix 28 oxigen and 72 azot, that th« 



mixture diminiQies nitrous gas more than air, and fupports 



combuition and animal life for a longer time. 



3.DifFercntcom- 3. Difierent combuftibles are capable of abforbing different 



u cb a or portions of oxij^en from a given quantity of air. Phofphorus 



titles of oxigen 22 per cent. Sulphur, 8, &c. — The only inferences 1 draw 



from common f^^p^ \.\\c{c facts are, that phofphorus will burn in oxigen of any 



denfity, that fulphur will not burn in oxigen unlefs it be of -f 



cf atmoi'pheric dcnfily or more. Tlie difference in the pheno- 



i> mena 



