1824.] . 
elastic force equal to the pressure of 
many atmospheres, will render the risk 
of explosion extremely, small; and,_ if 
future experiments should realize the 
views. here,,developed, the) mere .dit- 
ference, of. temperature between sun- 
shine and shade, and air and water, or 
the eflects.of, evaporation from a moist 
surface, will, be, sufficient ‘to. produce 
results, .which have.bitherto: heen ob- 
talb only» by.a great expenditure of 
fue Prat, % 
- I shall, conclude this communication 
by a few.general observations. arising 
out, of this enquiry, 
There. is;a simple mode of liquefying 
the gases, which at first view appears 
paradoxical, namely, by the application 
of heat; it consists in placing them in 
one leg of a,bent sealed tube confined 
by,,.mercury,, and. applying: heat to 
ether, or alcohol, or ;water, m ihe other 
end....In this manner, by the pressure 
of the-vapour of cther, L have Jiquefied 
prussic, gas and sulphureous. acid. gas, 
the vonly, two ‘on, which E have made 
experiments;);and these gases in being 
reproduced occasioned cold. 
There canbe -little doubt that these 
general, facts of the condensation of the 
gases, will have many. practical appli- 
cations,, /They: offer easy methods of 
impregnating «liquids with. carbonic 
acid) and, other gases,, without the ne- 
cessity,of common mechanical pressure. 
They affurd means of producing great 
diminations of temperature, by the ra- 
pidity, with» which large’ quantities. of 
iquids,may -be:rendered aeriform ; and 
as compression occasions similar effects 
to,cold,\in preventing the formation of 
elastic substances, there is great reason 
to believe that, it; may be: successfully 
employed for ihe. preservation of animal 
and. vegetable substances. for the pur- 
poses.of food... 9: dial 
On the Chaiiges of volume produced in 
Gases indifferent states of Density, 
by heat.” fn 
de Tn investigating the laws of the elas- 
tie fe eee exerted by vapours or gases 
raised from liquids by increase of tem- 
perature under compression, one of the 
me Important .circumstances. to: be 
roc. is.the rate of the expansion, 
or, What,is, cquivalent, of the elastic 
wig. iin is ' 
, 
Montury Mae, No, 390, 
Proceedings of Public Societies. 
537 
force, in atmospheres in different states 
of density. ‘hue 
It has been shown by the experiments 
of MM. Dalton and Gay Lussac, that 
elastic fluids of very different specific 
gravities expand equally by equal in- 
crements of temperature ;. or, as it may 
be more correctly expressed, according 
to the eclucidations of MM, Dulong’ 
and .Petit, that mercury and air, or 
gases, are equivalent in their expansions 
for any number of degrees in the ther- 
mometrical scale between, tle freezing. 
and boiling. points, of water; and the 
, early researches of M. Amontons seemed: 
to show thatthe increase of the spring 
or elastic force of air by increase of 
temperature, was in the dircct ratio of 
its density., I am not however ac- 
quainted with any direct researches 
upon the changes of volume. produced 
in gases in very different states of con- 
densation and rarefaction by changes of 
temperature, and the importance of the 
enquiry, in relation to the subject of 
my last communication. to, the society, 
induced me to undertake the following 
experiments. , ian} 
Dry atmospherical air was, included 
in a tube by mercury, and_its tempe- 
rature, raised from 32° Fahrenheit, to 
212°, and. its, expansion accurately 
marked, The same volumes of air, but 
of double and of more than_triple the 
density under.a pressure of 30 and. 65 
inches of mercury, were treated in the 
same manner, and. in the same tubes; 
and when the necessary corrections 
were made for the difference. of, pres- 
sure of the removed column of mercury, 
it was found that the expansions, were 
exactly the same, natin sis 
As apparatus was, constructed, , in 
which the. expansions of rare air con- 
fined by columns of- mercury, were, ex- 
amined and compared with the expan, 
sions of equal volumes. of air, under 
common pressure; when it appeared, 
that, for an equal. number, of degrees of 
Fahrenheit’s scale, and between 32° an 
212° they were precisely equal, whether 
the air was 4, 4,,or 4, of its natural 
density+\» SUF US Swiss tscratad ak 
Similar experiments were made, b ut 
they, were necessarily less precise, With 
air condensed six and expanded, Seen 
times, with similar results. jy 4.9 2), 
YURI A yaa Ww 
3Z NEW 
