On the Resistance of Fluids. 111 
Art. VII.—On the Resistance of Fluids, in reply to Mr. Blake; 
by Gzo. W. Keexy, Prof. of Natural Philosophy, Waterville 
salem 
TO PROFESSOR SILLIMAN. 
Str—WueEn I saw Mr. Blake’s first communication in Vol. xx1x, 
No. 2, of this Journal, in which among other novelties, he attacked 
the Newtonian demonstration of the law of resistance on direct im- 
pulse of a fluid, I did give it a very careful and attentive rd 
his repeated insinuation to the contrary notwithstanding. Io 
ed that his argument against that demonstration wore two a 
one bad for Mr. Blake, the other worse, according as his term “ force 
of resistance’ meant the action in an indefinitely short time, or in 
no time. ‘The bad is bad enough, as your readers must have per- 
ceived from my last communication, if not before; but bad as it is, 
the worse is, as will presently appear, so very much worse, that 
common courtesy forbade that I should, in that communication, even 
state the alternative. Mr. Blake, however, has eagerly vindicated 
his right to the worse, and thereby has, with some probably, gained 
a temporary advantage : of how much real value this is, shall soon 
be shewn. 
Understanding now that Mr. + Blake, by “force of resistance,” or 
“force,” means action in no time, 1 propose to prove, 
First, That Mr. B. has misunderstood ne meaning of the demon- 
stration he has attacked. 
To do this, I will first quote the demodetastiog as gives by Bros 
fessor Olmsted, in his Natural Philosophy. 
“ Both the number of particles which meet the plane, and the 
force of each, are as their velocity : hence the resistance is propor- 
tional to the square of the velocity.” This is also the argument of 
Newton and all his followers. 
Now, your readers will remember that in Mr. Blake’s first com+ 
paangoabr he undertakes to demonstrate that his “force of resist- 
ance,” or “force,” is as the square of the velocity. Then follow the 
two annexed sentences. 
* Since the area of the plane is given, the number of a in 
action atany moment is given, and consequently the force of each, 
at any instant, is as the square of the velocity of the plane.” 
* We may now note a fundamental error in the received theory, 
which assumes, usually without argument, that the force of each 
