Note 802 — Chapter V · (continued 2)

The account of these experiments was read before the Royal Society of Edinburgh in 1805, and is printed in their Transactions, vol. vi. pp. 71–185, Edinb. 1812, 4to. The general result was (pp. 148, 149), ‘That a pressure of 52 atmospheres, or 1700 feet of sea, is capable of forming a limestone in a proper heat; That under 86 atmospheres, answering nearly to 3000 feet, or about half a mile, a complete marble may be formed; and lastly, That, with a pressure of 173 atmospheres, or 5700 feet, that is little more than one mile of sea, the carbonate of lime is made to undergo complete fusion, and to act powerfully on other earths.’ See also p. 160: ‘The carbonic acid of limestone cannot be constrained in heat by a pressure less than that of 1708 feet of sea.’ There is a short, and not very accurate, notice of these instructive experiments in Bakewell's Geology, London, 1838, pp. 249, 250.