Note 68 — IV.[34] CARNOT’S THEORY OF THE MOTIVE POWER OF HEAT.[35] WITH NUMERICAL RESULTS DEDUCED FROM REGNAULT’S EXPERIMENTS ON STEAM.[36]

In different Cornish engines, the pressure in the boiler is from 2½ to 5 atmospheres; and, therefore, as we find from Regnault’s table of the pressure of saturated steam, the temperature of the water in the boiler must, in all of them, lie between 128° and 152°. For the better class of engines, the average temperature of the water in the boiler may be estimated at 140°, the corresponding pressure of steam being 3½ atmospheres.