SECT. II.] 
PROPERTIES OF STEAM. 
69 
Ure’s Experiments on the Force of Steam. 
Temperature of 
steam. 
Force in inches of mercury. 
Temperature of 
steam. 
Force in inches of mercury. 
Ure’s observa 
tions. 
By Rule 
page 59. 
Ure’s observa 
tions. 
By Rule 
page 59. 
24° 
0-170 
0-118 
190° 
19-000 
19-35 
32 
0-200 
0-172 
200 
23-600 
23-71 
40 
0-250 
0-245 
210 
28-880 
28-86 
50 
0-360 
0-37 
212 
30-000 
30-00 
55 
0-416 
0-45 
220 
35-540 
34-92 
60 
0-516 
0-55 
225 
39-110 
38-32 
70 
0-726 
0-78 
230 
43-100 
42-00 
80 
1-010 
1-106 
240 
51-700 
50-24 
90 
1-360 
1-53 
250 
61-900 
59-79 
100 
1-860 
2-08 
260 
72-300 
70-8 
110 
2-456 
2-79 
270 
86-300 
82-45 
120 
3 300 
3-68 
280 
101-900 
97-92 
130 
4-366 
4-81 
290 
120-150 
114-4 
140 
5-770 
6-21 
295 
129-000 
123-5 
150 
7-53 
7-94 
300 
139-700 
133-2 
160 
9-600 
1005 
310 
161-300 
154-5 
170 
12-050 
12-6 
312 
167-000 
159- 
180 
15-160 
15-67 
312 
165-5 
If a nice agreement with a particular set of observations had been attempted, 
the formula could have easily been arranged to represent these better; but by so 
doing it appears to me that the elastic forces would have increased in a higher 
ratio than we are warranted in expecting from other experiments, and the later 
inquiries of Mr. Dalton justify the numbers being higher at or about 150° than 
Dr. Ure’s. 
99. Mr. Southern’s experiments on high pressure steam were made with a 
digester, with a thermometer fitted to a metallic tube, so that the stem of the ther 
mometer might be immersed as far as it contained mercury. Also, instead of 
measuring the force of the steam by a loaded valve, a nicely bored cylinder was 
used, with a piston fitting it so as to have very little friction, to the rod of which a 
lever was applied, constructed to work on edges like those of a scale beam; and 
that no error might arise from this construction, a column of mercury was substi 
tuted, and the correspondence was within tvo of an inch. 
The observations at each of the points of temperature and pressure were con 
tinued some minutes, the temperature being alternately raised and lowered, so 
as to make the pressure in excess and defect; and a mean temperature was taken 
for the result. This method seems to me entitled to great confidence, and hence 
I have made the results the principal data for my formula. (See art. 86.) 
The experiments below 212° were conducted nearly as Dr. Robison’s, and those 
below 62° were made by Mr. W. Creighton. These low pressure experiments do 
not seem to be of equal value with the four high pressure ones.