^82 M. Seguln 07i the Effects of Heat and of Motion, 
The first is the quantity of motion which is suddenly de- 
veloped by a glass tear (Prince Rupert’s Drops), which has been 
dropped red-hot into water, when the slightest derangement has 
taken place in some of its parts. 
The second relates to the effect of the steam-engine ; for, if 
we consider the cause of it to be the caloric, it is not easy to see 
why we could not produce an indefinite number of oscillations 
with the quantity of caloric necessary to produce the first, if w'e 
could by any means whatever employ the low temperatures 
which are lost, to renew the effect. Whilst, if, as we suppose, 
an angular motion has been changed into a rectilineal motion, 
or into a motion of translation, we should find, after the effect, 
only the quantity of motion, or the caloric, which has not been 
employed in producing the useful effect. 
The third fact consists in giving a satisfactory explanation of 
the great cold which exists in the higher regions of our atmos- 
phere, whose temperature on the contrary, ought to be more 
elevated, by the quantity of caloric abandoned by condensed va- 
pours, and the warmest gases, which tend upwards, by their ex- 
treme levity. 
If we apply our theory to this case, we shall observe, that a 
gaseous body, on escaping at a tangent, in a direction contrary 
to that of its gravitation, is subject to the same laws as all other 
bodies in similar circumstances ; and that, consequently, when 
it has arrived at the limit indicated by its initial velocity, it 
is found at rest, or, in other words, deprived of its caloric, 
and obliged to absorb a new quantity from surrounding bodies, 
in order to be reconstituted with the quantity necessary to de- 
termine its existence in any state whatever. 
The fourth fact relates to the motion produced by organised 
bodies, and may be explained in the same manner as the steam- 
engine, which appears to me, in a great state of simplicity, to 
resemble, in a high degree, the vital functions, enjoying^ like 
them, motion and heat, while it is furnished with oxygen and 
fuel. 
If you consider these views, on a subject of vast extent, as 
meriting to be submitted to the distinguished members of your 
Society, I do not doubt, that, when viewed in the aspect in 
which I have been able to place them, they will not be able to 
