int 
precedence; but it had declined in duty to 85- millions per bushel, 
or 101-3 per ewt. 5 
In 1838 the Wheal Darlington engine again took the lead with 78-1+* 
millions per bushel, or 93° per ewt ; 
,», 1839 ,, Fowey Consolidated Mines engine regained the first 
place 77-8* millions per bushel, or 92°7 per ewt; 
,, 1840 ,, Wheal Darlington engine once more assumed the lead 
with 81:7* millions per bushel, or 97:3 per cwt. 
Both these, however, were excelled by an engine, of eighty-five 
inches cylinder, erected by Hocking and Loam at the United 
Mines,t which performed in . 
IGVOL ooodus 101:9* millions per bushel, or 121-8 per ewt. 
1GY) %Gc006 TOA op 5 », 128-1 Be of coal. 
eV oob000 COESY op os », 114:5 fs 
The system of combined cylinders—modified by placing one’ 
above the other, and admitting the steam above the smaller and 
upper, and allowing it to expand thence beneath the larger and 
lower piston§ was introduced, for a third time, at Carn Brea 
and Great Saint George, by James Sims;|| but notwithstanding 
the high duty of from 88- to about 100° millions§] was reported 
this form of engine again failed to secure favour, and its use has 
been discontinued.** 
With improvements—if any have been made—since 1843,{+ 
T am unacquainted. 
* «The boilers [of Taylor’s engine at the United Mines] were made 
““smaller in diameter than usual, and of stronger plate, so as to stand a 
‘higher pressure of steam”... Also, an extra number of boilers was pro- 
vided, . . . and the strength of the working parts. . . was augmented to 
withstand the strain. . . at the commencement of the stroke. 
It was first reported in December, 1840 at........ 74:9 millions. 
in July, 1841 it passed.. 100-9 saad 
September, 1842 A 107°5 39 
1843 » 1s ae 
Pott, Cornish Pumping Engine, pp. 68-70. 
+ Combes, L’ Exploitation des Mines, iii., pp. 524, 541, 553, 555, Pl. lxii., 
Fig. 1. 
{ Phillips and Darlington, Records of Mining and Metallurgy, p. 62. 
§ Pole, Cornish Pumping Engine, pp. 69, 135-1387. Combes (Piot), 
L’Exploitation des Mines, iii., pp. 615-16. Husband, Proceedings of the 
Inst: of Civil Engineers, xxiii., p. 77. 
|| James Sims (second son of William Sims) was born at Treskerby in 
Gwennap, 29th January, 1795, and died at Redruth, 30th October, 1862. 
q Pole, Cornish Pumping Engine, p. 69. Combes (Piot), L’EHaploita- 
tion des Mines, iii., p. 616. 
** Husband, Proceedings of the Inst: Civil Engineers, xxili., p. 77. 
++ From 1843 to 1858 my time was mostly passed in other countries ; 
since then it has been entirely occupied with other subjects (Cornwall Geol: 
Trans: Viii., pp. 1-xxxii., i-vil., 1-916). 
