97G 
MR. 0. REYNOLDS ON THE MOTION OF WATER AND OF 
critical point, their intersection is at a constant distance from this point which in 
the logarithmic curves is, both for ordinates and abscissse, 
0-154 
These points o are therefore given by 
T)H 
loo - — c = lo 
p 2 . 
D H 
'"-pr +0T54 
Therefore putting 
log^=log D ;° +0-154 
A= DV B = I+ U 
log A= log A C +0T54 
log V>— log B c +0*154 
and by the values of A c and B c previously ascertained (Art. 33, p. 971), 
log A = 8 - 8311 A=67,700,000 
log B = 2'598 B= 396-3 
We thus have for the equation to the curves corresponding to the upper straight 
branches 
. D 3 . DoVW 
a p 4= ( b T 
is 
And if n have the value 1 or 1 *722 according 
< or > 1 the equation 
as either member of this equation 
n 
is the equation to a curve which has for its logarithmic homologue the two straight 
branches intersecting in o, and hence gives the law of pressures and velocities, except 
those relating to velocities in the neighbourhood of the critical point, and these are 
seldom come across in practice. 
By expressin 
T>v 
g n as a discontinuous function of B 6 .q ( the equation may be made to 
fit the curve throughout. 
38. The effect of temperature .—It should be noticed that although the range is 
comparatively small, still the displacement of the critical point in Tables III. and IV. 
is distinctly marked. The temperatures were respectively 9° C., 5° C. 
At 9° log P" 1 = 0-12093 
At 5° log P- 1 = 0-06963 
Difference = "05130 
