Ix 
The numbers—of mines wrought in Cornwall,—of the engines 
by which they were drained,—and of such of these as were re- 
ported on by the Registrars, at various times, are shown (approxi- 
mately) in the following columns ;— 
MINES. Engines (Pumping). 
Dates. § | —— av vem re | —————__~ 
Tin. Copper. Lead. Total. | At Work. | Reported. 
1S1GNe ——— | 42% es) | |, GG 
IGA || = eek a eee | ore 
1838) |) ——= a | Gs || eos | Bie 
1848 83]| 23\| | ee ABA 
1858 | 137** | 157]| 46]| 340 —— | aaa 
1868 | 1054+ | so¢¢ | 17+4 | 20244 25+ 
It is manifest that results derived from the small number of 
engines lately reported, cannot represent an average performance 
throughout the County. 
Various causes—the more frequent use of diagonal engine- 
shafts,tt—the increased depth of the mines,§§—the wear of the 
* Hxclusive of mines which yielded less than ten tons each, and of such ~ 
as sold ores by private contract. Carne, Cornwall Geol: Trans: ii., p. 429. 
+ Ante, p. 58. 
+ Exclusive of mines which yielded less than fifty tons each, and of such 
as sold ores by private contract. Carne, Cornwall Geol: Trans: iv., p. 492. 
§ Henwood, /bid, v., pp. 464-475. 
|| For these particulars, I have to thank Mr. Robert Hunt, F.R.S., 
Keeper of Mining Records in the Royal School of Mines; and Mr. Henry 
Williams, of Alma, near Truro. 
q Ante, p. 58. 
** Hunt, Journal of the Bath & West of Engla nd Agr raceme XVi. 
+t Hunt, Mineral Statistics, 1868, pp. 5-7, 19-21, 36. 
nhateyice The practice of sinking the engine- shaft, for the whole .... or for 
‘a part of its depth, in a direction inclined or diagonal to the course of the 
“lode instead of perpendicularly, has increased of late years.... In August, 
“©1841, of 53 engines reported, 27 drew their load perpendicularly ; 22 drew 
“perpendicularly from the surface to the intersection of the engine-shaft 
‘‘with the lode, and below that point diagonally; and 4 drew diagonally 
‘from the surface. Of 24 engines reported in August, 1860, 7 drew per- 
“pendicularly ; 10 partly perpendicularly and partly diagonally; and 1 
“diagonally. Thus in.... 1841, 51 per cent. of the engines reported, drew 
‘perpendicularly ; but in August, 1860, only 28 per cent.” Morsurap, Pro- 
ceedings of the Institution of Civil Engineers, xxiii., p. 47. 
‘Diagonal shafts were more in use now than formerly.” HusBanp, 
Ibid, p. 75. 
“Oblique rods. .. run against friction-rollers; [they], however, not only 
‘sive much friction, but are expensive and troublesome to keep in order.” 
Por, Cornish Pumping Engine, p. 120. 
gg “In... 1840 the [entire] length of the lifts attached to each engine 
‘‘ faveraged 144-3 fathoms; in..1860 it was 173°5.” MorsHEap, Proceedings 
‘of the Inst. of Civil Engineers, xxiii., p. 48. 
