78 General Reflections on Heat. 
separately, men the semi-oval receiver, and subsequently re- 
ee 
The Eadiemeters (figs. 6 and 7.), with the accompanying 
semi-oval glass vessel. (fig. '.) may be empioyed with the 
dissolved sulphurets, or with solutions of iron, impregeated 
with nitric oxide in the following way. Let a smail phial, 
with a mouth large enough freely to admit the point of the 
Eudiometer, be fied with the solution to be used. Intro- 
duce into the bottle, over the pneumatic cistern, 300 mea- 
sures of the air or gas to be examined. Transfer the bottle, 
still inverted, to a small vessel containing water, or a quantity 
of the absorbing fluid used in the bottle, adequate to covet 
the mouth of the phial, and compensate the absorption. 
When there has been time enough for the absorption rye be 
completed, transfer the residuum to the receiver (fig 8.), 
measure as in the case of nitric oxide. 
soon as 1 can make a sufficient number of ge 
observations with the various Eudiometers, of whic ave 
now given an account, I will send them to you for soblichtas 
ArT. KcGeneral Reflections on Heat. 
To THE EDITOR OF THE AMERICAN JOURNAL OF SCIENCE. 
Dear § 
Tae following observations on heat, fovsied originally 
one of the concluding lectures of a course of chemical instruc- 
tion. I beg leave to retain the form in which it was address- 
ed to my pupils, on account of the difficulty I have experi- 
enced in attempting to mould the matter into the shape of an 
essay. | am induced to offer it for publication, not with the 
hope of instructing proficients in the science o istry, 
(who will find in it little that is new) but with the belief that 
it presents some considerations, which may be interesting to 
another class of your readers, who are not peneainy de- 
voted to this science. M oie 
ost re y ours, ; 
Maton ee gorbe elt Ke 
