MR. T. E. STANTOR OR THE PASSAGE OF HEAT BETWEEX 
of each of the quantities Tq, t, (Tq — t) 'p, v and r. on the rate of transmission, can 
be studied separately. 
Thus, in determining the effect of the velocity of the water, a series of experiments 
were made at varying velocities, but in which the values of Tq, h; (-0 “ h)> 
remained constant. 
1.—Effect of the Varying Pressures of the AVater, Tq, (Tq — h); t, and r constant. 
The following table gives the results obtained : - 
Diameter of 
pipes. 
Temperature 
of surface. 
Initial 
temperature 
of water. 
Final 
temperature 
of water. 
Velocity of 
water. 
Pressure in 
centims. 
of mei’cury. 
Rise of 
temperature. 
1-07 
60°4 
0 
25-6 
34-6 
1160 
94-0 
9°-0 
107 
60’4 
25-4 
34-3 
116-0 
113-0 
8°-9 
1-07 
60-4 
25-3 
.34-4 
116-0 
152-0 
9°-l 
1-07 
60-4 
25-3 
34'5 
116-0 
191-0 
9°-2 
These results show that for the given range of pressure, t.e., from one to two 
atmospheres, the transmission is practically independent of the pressure. 
IT.— Effect of Variation of Velocity, Tq, (Tq — ?i), and r constant. 
About 50 experiments of this kind were made. As an example of the results the 
following table may be given :— 
Diameter of 
pipes. 
T 
-* !)• 
h- 
h- 
V, 
Rise of 
temperature. 
1-39 
47-55 
17-98 
24-45 
69-0 
6°-47 
1-39 
47-55 
17-99 
24-08 
98-0 
6°-09 
1-39 
47-55 
18-00 
23-92 
123-2 
5°-92 
These results show tliat tlie increase in temperature of the water for the given 
range of temperature, &c., is nearly independent of the velocity. Thus, for an 
increase in the velocity of 80 per cent., the rise of temperature is only 8'5 per cent, 
less, or in other words, the heat transmitted for the given range of temperature 
is nearly proportional to the velocity of the water! Those experiments were repeated, 
and then tried with a different value of the range (Tq — t^), but with the same 
results, the ramges of temperature varying from 5° to 40b 
