175 
the resolvent product brings it into relation with that of 
Lagrange and Vandermonde, yet that better results may be 
deduced by applying it to Euler’s and Bezout’s theory, and 
without supposing that product to vanish. 
A Paper was read by J. P. Joule, LL.D., F.R.S., 
entitled, “ Experiments on the Total Heat of Steam.” 
The Author showed that what is called the total heat of 
steam, or the quantity liberated when steam is condensed into 
water of 0° centigrade, consists of, 1st, The true heat of 
evaporation ; 2nd, The heat due to the work done on the 
steam during the condensation ; and 3rd, The heat liberated 
by cooling the water from the temperature of condensation 
to the freezing point. The determination of the total heat 
of steam had been made the object of a very careful and 
elaborate research by Regnault, but it appeared to the 
Author that independent experiments conducted in a different 
and more direct manner would not be without interest. The 
following is a summary of the results obtained by him, com- 
pared with those of Regnault. 
Total Pressure 
of Steam 
in Inches. 
37*25 
57*52 
111*58 
Total Heat in Degrees Centigrade. 
^ , 
Author. Eegnault. 
638*43 638*77 
644*77 642*87 
655*45 649*06 
A Paper was also read by Dr. Joule, entitled, “ On a 
Method of Testing the Strength of Steam Boilers.” 
The Author adverted to the means hitherto adopted for 
testing boilers. 1st. That by steam pressure, which gives 
no certain indication whether strain has not taken place under 
its influence, so that a boiler so te.sted may subsequently 
e.xplode when worked at the same or even a somewhat less 
degree of pressure. He trusted that this highly reprehensible 
practice had been wholly abandoned. 2nd. ’Phat by hydraulic 
