Note 32 — III. REFLECTIONS ON THE MOTIVE POWER OF HEAT, AND ON MACHINES FITTED TO DEVELOP THAT POWER.[4]

We find in the work called De la Richesse Minérale, by M. Heron de Villefosse, vol. iii. p. 50 and following, a good description of the steam-engines actually in use in mining. In England the steam-engine has been very fully discussed in the Encyclopedia Britannica. Some of the data here employed are drawn from the latter work.