OF STEAM AT DIFFEEENT TEMPEEATUEES. 
221 
The foUo'W’ing Table gives the value of the coefficient of expansion of superheated 
steam taken at different intervals of temperature from the maximum temperature of 
saturation. 
Table showing the Coefficient of Expansion of Superheated Steam. 
Number of 
Maximum 
Temperatures between 
Coefficient of 
Coefficient 
experiment. 
temperature 
which the 
expansion 
expansion of 
of expansion 
of saturation. 
IS taken. 
steam. 
of air. 
1. 
13^-77 
140 , 
170 
As 
1 
2. 
155-33 
160 , 
190 
5 .5 6 
1 
3. 
159-36 ( 
159-36, 
170-2 
1 
150 
1 
6 1 8 
t 
170-2 , 
209-9 
6 2 4 
1 
6 2^ 
5. 
171-48 1 
171-48, 
180 
1 
2 U 0 
6 3 0 
180 , 
200 
1 
6 0 4 
1 
639 
6. 
174-92 1 
174-92, 
180 
1 hTJ 
_1_ 
6 3 4 
180 , 
200 
_i_ 
6 37 
ir3^ 
f 
182-3 , 
186 
2^ 
1 
7. 
182-30 { 
6 4 1 
1 
186 , 
209-5 
630 
As 
8. 
188-30 
191 , 
211 
6 0 4 
1 
(TsTi 
1'. 
242-9 
243 , 
249 
5 17 
1 
T02 
r 
257 , 
259 
1 
1 
4'. 
255-5 { 
264 
3 9^ 
1 
257 , 
6 1 0 
tI'S' 
r 
268 , 
271 
1 
6'. 
267-21 
2 10 
7 2 5' 
271 , 
279 
1 
6 4 0 
tIu 
f 
271 , 
273 
1 
1 
7'. 
269-2 
2 3 2" 
Ta 0 
273 , 
279 
_L_ 
1 
5 5 1 
7 3 3 
r 
283 , 
285 
-j. 
1 
9'. 
279-42 { 
2 9 8 
T42 
1 
285 , 
289 
1 
5 3 3 
At 
r 
297 , 
299 
1 
■sEr 
13'. 
292-53 
2 8 1 
7 5 6 
299 , 
302 
The results recorded in this Table distinctly show that, for temperatures within about 
ten degrees from the maximum temperature of saturation, the rate of expansion greatly 
exceeds that of air, whereas at higher temperatures from this point the rate of expansion 
approaches that of air ; thus, for example, in Experiment 6, between the temperatures 
of 174°-92 and 180°, the coefficient of expansion is yiw! is, about three times that 
of air; whereas between the temperatures of 180° and 200° the coefficient of expansion 
is very nearly the same as that of ah’, and so on in other cases. At temperatures 
somewhat removed from the maximum temperature of saturation, the coefficient of 
expansion in the high-pressure experiments is decidedly greater than that of air, 
whereas in the low-pressure experiments it does not greatly differ from that of air. 
The mean of Sj in the latter case =:|(453 + 406-|-467-l-424 + 457+444+413) = 438. 
whilst for air this constant is 459. 
