GAS. 
ane by Prieftley; but this feems rather to imply that 
ftie fluids are oy seer igriae “ common Gr atmofphe- 
ric air, the contrary t which ib to be true. 
The term gas is ee ee cee 
Though the ebfervations of Van aad Boyle, Hales, 
Black, and Cavendifh, feemed to leave no doubt that there 
Pi no y diftinct 
the ee ae “of Prie 
d the fphere of paar 
Since then moft chemical enquiries have been con- 
neCted with the tse tee of gafeous bodies, and great ad- 
‘dition has been made tothe number of gafes and to the know- 
ledge of diftintive properties. Elaftic fluids — in 
fa& been divided into two genera, gafes and vapours ; the 
former Bg fuch eee flu ids as retain their a in 
all Known t pera e latter fignify ftic flu ids 
which Tole their cla(teity by cold, and become liquids, &c. 
‘This diftinGtion may have its ufe ; but there i is great reafon 
' to believe the difference is not in kind but in degree only ; 
and that all the gafes would lofe ee elafticity provided the 
temperature could be fufficiently uce 
e mechanical Apidae s of the gates, or thofe 3 
to their yr us gravitating energy bei as far 
known, the fame as thofe of the gael ee: a be fiaicd 
under the h me of Preumatics. The other general pro- 
perties, which fall rather under a chemical than mechanical 
head, will be pointed out and explained i in what follows ; 
and a more ria account of each gas will be found under 
its Siena 
ae ie confidered as fimpk or compound. ~The fim- 
Ee ales, according to our prefent knowledge, are three ; 
mely, 
thofe ela 
i. Hy drogen 
z. Oxygen 
pone or nitrogen 
4. Carbonic acid, from carbon and oxygen 
8. Carburetted hydrogen, si rtydre and ayaa 
- Olefiant gas, from carbon 
‘Sulphuretted hydrogen, ae chee and hydro- 
rn. I. aap acid, Lia fulphur and oxygen. 
12. Fluoric acid, from hydrogen and oxygen? 
13. Muriatic acid, fan hydrogen and oxygen ? 
Yh. ren aeseaae acid, from ane acid and oxygen. 
15. Am acal gas, ‘from az ydroger. 
16. Phofphuretted hy drogen, Won phofpherus and hy- 
drogen. 
= ‘Arfeniuretted hydrogen, from arfenic and hydro- 
“8. Nitric acid, from azote and oxygen. 
1g. Nitrous acid, from azote and oxygen. 
20. Aqueous vapour or fteam, from oxygen and hydro- 
gen. 
21. Alkoholic vapour, from carbon and oo 
22. Ethereal vapour, from sphere and h 
in all "he lor a is 
0 
‘Though Berthollet and fome others conceive 
eertain i to contain ¢hree elements; namely, carbon, hy- 
and oxygen, and hence denominate them owy-carbu- 
ae aca yet they have given no decifive proof of 
the exiftence of fuch gafes. ee it is almoft obvious that 
oxyd, d hydrogen fré 
may well hefitate ; erm fuch ‘diftingtion till fome one can 
point out a method of obtaining a gas uniformly the fame, 
es which cannot be he rocure ears mixi a: above 
ree .or any ny ers any ae vas onttitu- 
ui 
We thall ra — ft. The ais of wale — ; 
2d. The na of compound gafes ure of 
gafeous inl aad, ath. We fhall cbibit re erg 
the more rema-kable properties of the gafes in one pomt 
view, with cuit &e. 
1. The Nature of fimple Gafes.—The conttitution of an 
elaftic fluid was firit pointed out and demonitrated by New- 
ton in the 23d prop. of the fecond book of the Principia ; 
namely, that it pee of particles which repel one another 
y a force which varies in the {imple inverfe ratio of the cen- 
S. t leaf a fluid fo conitituted would exhibit 
the fame mechanical properties as atmofpheric air the 
nature of this repulfive power there have been feveral frees 
lations; fome have imagined it to be magnetical; others 
electrical ; and others, with more feeming probability, have 
afcribed it to heat. eed, when it is confidered that the 
clafticity increafes and diminifhes with the temperature to 
the moft diftant points we can attain, heat muft he 
pal if not the fole caufe of aerial repulfion. id 
particle of an elaftic fluid may be fuppofed an indefinite] 
{mall, hard, and indivifible body, furrounded by an infinitely 
fine and fabiile fluid, heat, igs ee ae of atmofphere 
ording to c. = atmolphere will be of great- 
eft denfity xt tthe ee of ae ae le, and of lefs denfity 
in fome proportion to the diftan 
‘Mr. Daltonhas developed and ‘extended this notion, of heat 
being the caufe of repulfion, in his New Syftem of Che- 
mical Philofophy. He deduces a very curious conclufon 
and very important one, if it be true, that all elaftic fluids 
nen th 
a greater number of them in 
clufion be correét, the capacities of elaitic fluids for heat” 
will be proportional to the number of their particles i ina 
data, the accuracy 
ble, he derives a heats agreeable to the above hypo- 
thefis, as follo 
Relative Weights Specific Heat of 
; of ultimate Particles. equal Weights. 
titan - - - I - ~ 9.382 
ae ~ = - § - - 4.866 
- F - -. Tf 
Atmotpheic air - - Oo - - ae 
Nitrous - - 12 - - 2777 
Nitrous ae - - 17 . - 549 
Carbonic acid - - 19 - - 491 
m: - = GC - = L555 
Carburetted hydrogen - 7 - - 3 
1.333 
Olefiant 
