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AO : Dr. John Garric on the 
In acquiring a right understanding of the part it plays i in-the gen- 
eral system and economy of nature there is a gratification inde- 
in t 
solution of the question, “ what is ote —, of heat given-out 
the condensation of air 2” there is a more immediate interest 
arising from the practical to wohsink the fact may be applied. 
It is favorable to the intered’s of science that the prospective value 
of the knowledge has justified- experiments on this subject, as 
objects of commercial speculation ; for otherwise its full elucida- 
tion would require an outlay of money too heavy to be expende 
by the mere lover of nature. 
The atmosphere, from any thing we can observe ‘taking place — 
in it, affords but a remote and insignificant idea of the extensive 
relation existing between it and heat. Our sensations may indi- 
cate suffering from diminution, or inconvenience from exaltation 
of temperatire, and the thermometer may mark the extent of its 
that it contains more of the principle of heat, in proportion to its 
absolute quantity of matter, than any other body found in a natu- 
ough not experimentally demonstrable, it cannot 
be doubted that the aerial form of the atmosphere, like that of 
ial is caused by the presence of a definite amount of heat. 
be condensed and dilated any number of times, and 
inte: will be with each change, a simultaneous and proportional 
diffusion and absorption of heat. The determination of the 
quantities of caloric thus alternately set free and rendered latent, 
is, apparently, a simple problem, which it is generally thought 
can be easily solved. But to furnish precise results not only 
is science and experimental skill demanded, but quantities of — 
facilities for manipulation, such as private philosophers can 
command. It is true that if “instruments be exceedingke ex- 
act, a n experimenter be fully equal to the task of using 
them properly,” the error upon moderate, may be quite as small 
in proportion as upon large quantities of most substances. but 
in this assumption, qualifications are implied to which few ex- 
perimenters can lay claim; nor when possessed, would they be 
adequate to insure perfect accuracy in operating upon so attenu- 
ated a fluid as air which larger apparatus might attain. 
In the attempts to determine the quantities of heat set free or 
absorbed by changes in the volume of air, these principles are well 
* According to t are considered the most accurate experiments hail: peers 
tions on this su aoa ct, age absolute heat of ‘atmenyherie air, satire ah from the 
standard of kg absolute heat of water, viz, 1,000—is 18. 000. on the 
air, page 1 
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