I7 o NATURAL HISTORY 
fir timber upon them, they difpofe conveniently of a great part of 
the deads \ an ceconomy which has two good effects ; it faves the ex- 
pence of bringing thofe deads up to the furface, and, by filling the 
fiflure at proper intervals, it prevents the adjoining ftrata from preff- 
ing the walls of the fiflure together, which might otherwife be of 
fatal confequences. That the common labourers may be employed 
without confufion in breaking and railing the ore, the captains fee 
that they be properly difpofed in the feveral parts of the mine j that 
they have neceflary tools and implements ready provided ; they 
are to examine the ffate of the mine, and provide for its fecurity ; 
fee that the adit be found and clear, that the ffiafts, hollows and 
loofer parts of the mine, be well propped with timber ; they are to 
to fee that proper communications be made and maintained between 
the feveral works of the mine * ; more efpecially are they to infped 
the ores, infift that they may be as fpeedily broke, as carefully fe- 
parated from the deads and from each other, and as honeffly 
brought up for the owner’s ufe, as may be. But indeed their 
chief care, and what requires their conffant Ikill and attention, is 
the management of the water, which in the Cornifh mines is ge- 
nerally very troublefome, every cranny that is cut throwing forth 
it’s water into the cavity where the miners work. To obviate this 
inconveniency the captain fhould be a kind of engineer, and well 
know how to collet, divert, and condud, as well as raife the 
water. It is not expeded indeed that the captains of mines fhould 
know how to build, repair, or redify the feveral engines ; for 
fuch purpofes there is a profeffed undertaker, or engineer, but the 
captain is to take care that the engineer has immediate notice as foon 
as any thing goes amifs, that he has proper materials, and without 
delay attends to remedy the diforder. In order to this, the water 
muff be convey’d over and befide the paflages, and crofs the open- 
ings of the mine by fide drifts and gutters, fo as all that poffibly 
can may run off by the common drain I, 1 ; what is below that 
level muff be colleded and drawn up to the adit. Where there 
are two lodes (as here, Pi. XVIII.) there muff be duds of commu- 
nication, as / a , Qjz, Fig. 11. which ferve to convey the water of 
the north lode into the ciftern <?, made in the fouth lode. 
sect. xiii. From fuch cifterns, judicioufly placed, the water is raifed to the 
Hydraulic^ ac q t fometimes by large buckets (in the Cornifh tongue called 
fn Cornwall. Kibbals) beft managed by the engine called the Whim, confiding of 
a perpendicular axis, on which turns a large hollow cylinder of timber 
(called the Cage) round which the rope (being direded down the fhaft 
s See horizontal planks from 5 to 6, and from 7 to 8, Fig. 1, L n. PI. xvm. * See m m, Q_a, Fig. n. ib. 
by 
