78 H.W. Blake on the flow of Elastic Fluids through Orifices. 
given of its composition. In the process of digestion it probably 
takes up the elements of water and is transformed into ammonia 
and glucose; the latter absorbed by the coats of the stomach 
finds its way directly into the circulation, or perhaps converted 
into fat becomes an element of the chyle, while the ammonia 
in a saline combination is excreted by the ordinary channels. 
Baron Liebig in his ee admirable researches in animal chem- 
istry,* has shown that the flesh-fluid of both herbivorous and 
carnivorous animals pint free lactic acid, and M. Bensch has 
found that the milk of dogs fed entirely upon flesh affords milk 
sugar. From the results of the decomposition of gelatine, there 
can be no doubt as to the source of both these substances, whose 
origin it would otherwise be difficult to explain. 
It is believed that a somewhat similar view to that we have 
taken of gelatine, may be extended to the proteine compounds, 
and one which will tend to settle the vexed question of its na- 
ture ; some ey upon this may form the subject of another 
communica 
Montreal, el at, 1847. 
Arr. XII—Of the Law which governs the flow of £lastic 
Of t 
Fluids through Orifices ; by Exx W. Buaxr. 
Tue subject announced at the head of this article, is not only 
interesting considered simply as a subject of scientific i inquiry, 
but it is also a matter of practical importance in its relations to sev- 
eral branches of mechanism. Among these may be instanced, as 
perhaps first in importance, the bearing of the subject upon the 
construction of the steam-engine The size of the pi s 
valves which conduct the steam to and from the working cylin- 
der, should be properly adjusted to the size and velocity of the 
piston. In general, the larger these pipes and valves the better, 
so far as respects the power of the engine. But there are incon- 
veniences attendant on making them large ; and in order to make 
a due compromise between the inconvenience that may be in- 
curred on the one hand, and the amount of power that may be 
sacrificed on the other, it becomes necessary to understand cor- 
rectly the law which governs the flow of elastic fluids through 
orifi 
ces, Treatises on the dynamics of fluids have not omitted 
to give rules for the determination of such questions; but it 
be — in the course of this article that those rules are very 
~ Beker _* See Am. Jour. of Science, ii ser., iv, p. 135.. 
Bile ae eee 
Se ae Epos 
