SECT. II.] 
PROPERTIES OF STEAM. 
71 
102. The force of steam at high temperatures is still wanting to complete 
the experimental part of the inquiry. A few experiments have been made, which 
appear to me to be entitled to some confidence, by Professor Arsberger, of Vienna. 1 
Arsberger’s Experiments on high Pressure Steam. 
Temperature of 
the steam. 
Force in inches of mercury. 
By experiment. 
By our Rule 
page 59. 
232° 
44-4 
43-56 
249 
59-1 
58-7 
274 
88-8 
89-0 
322 
176-0 
183-6 
372 
3250 
362- 
432 
620-0 
737- 
Here the rule is in excess at 432° by more than one sixth; but in an ex 
periment reported by M. Clement, to M. Poisson, 2 the force of steam at 419° 
is said to be 35 atmospheres, or 1050 inches of mercury, while our rule gives only 
635 inches. I doubt the accuracy of the statement. 
103. M. Cagniard de la Tour 3 made some essays to ascertain the space and 
temperature in which a given quantity of water became wholly steam; but from 
the frequent rupture of the glass tubes, and their loss of transparency, it was 
difficult to obtain a result. He states, however, that at a temperature but little 
removed from the melting point of zinc, water could be converted into vapour in 
a space nearly four times its volume. If this could have been really ascertained 
with accuracy, it would have given an important datum; but on the above rude 
approximation no reliance can be placed. 4 
1 Bulletin des Sciences Tecli. vol. i. p. 294. 2 Philosophical Magazine, vol. lxi. p. 60. 
3 Philosophical Magazine, vol. lxi. p. 58. 
4 In a paper on the elastic force of steam which has just been published by Mr. Ivory, in the 
4 Philosophical Magazine,’ a completely different process is followed for calculating the force of 
steam from that I have given; it does not however afford results much nearer to the experiments 
it is founded on, than those by my formula, while it is somewhat more difficult to apply, and 
becomes erroneous in high temperatures. 
Counting t the temperature from 212° and /the elastic force, his formula is 
lo K ._Z_= -0087466 t - -000015178 t°~+ -000000024825 
s 30 
It is derived from a comparison of Dr. Ure’s experiments; and the following table shows the 
results by those experiments, by Mr. Ivory’s formula, by other experiments, and by my formula.