1 823 .] On the Temperature of Mines, 447 



III. The third and last paper we have to abbreviate is by Dr. 

 J. Forbes, late Secretary of the Society (Trans, ii. 159 — 217). 



1. liuel Neptune. — Copper mine, situated in killas. Heiojht 

 above the level of the sea, about 200 feet. Depth, at the period 

 the observations were made, 550 feet. (Depth in 1822, 750 feet.) 

 Number of men employed under ground 120. Expenditure of 

 candles per month 1200 lbs. Expenditure of gunpowder ditto 

 250 lbs. Quantity of water discharged per day 216,000 gallons. 

 Temperature of this at the adit at the time the observations were 

 made 60°. (in 1822, 62"*.) Has been working 11 years (1822). 



2. Botallack. — Tin and copper mine. Height above the level 

 of the sea about 40 feet. Depth at the time the observations 

 were made, 570 feet. (Depth in May, 1822, 672 feet). Number 

 of men employed underground 150. Expenditure of candles per 

 month 1200 lbs. Expenditure of gunpowder ditto 600 lbs. 

 Quantity of water discharged by the pump daily 57,600 gallons. 

 Temperature of this at the adit "in 1819, 62°, in 1822, 67^. Has 

 been worked 17 years (1822). 



3. Little Bounds. — Tin mine. In killas and granite. Height 

 above the level of the sea 72 feet. Adit at the sea-level. Depth 

 from the surface 604 feet. Number of men employed under 

 ground 25. Expenditure of candles per month 48 lbs. Expen- 

 diture of gunpowder ditto 60 lbs. Quantity of water discharged 

 by the pumps daily 69,000 gallons. Temperature of this water 



This mine has been worked 30 years, but very little has been 

 done in it of late years, and the water has consequently risen in 

 it, to the 40 fathom level under the adit, that is, to the height of 

 192 feet from the bottom : it is kept under at this level by the 

 partial action of the engine. 



4. Ding Dong. — Tin mine. In granite. Height above the 

 sea level about 400 feet. Depth from the surface 606 feet. 

 Number of men employed underground 120. Expenditure of 

 candles per month 900 lbs. Expenditure of gunpowder ditto 

 300 lbs. Quantity of water discharged by the pumps daily 

 50,000 gallons. Temperature of this at the adit, 61°. Has 

 been worked eight years. 



5. Huel Vor. — Tm mine. In killas. Depth from the surface 

 948 feet. Number of men employed underground 548. Expen- 

 diture of candles per month 3000 lbs. Expenditure of gunpow- 

 der ditto 3500 lbs. Quantity of water discharged per day 

 1,692,660 gallons. Temperature of this at the adit 67°. Has 

 been worked 12 years. 



6. Dolcoath. — Copper mine. In killas. Height above the 

 level of the sea about 300 feet. Depth from the surface in 1819, 

 1386 feet ; in 1822, 1428 feet. Number of men employed under- 

 ground (1822) 800. Expenditure of candles per month 6000 lbs. 

 Expenditure of gunpowder ditto 2600 lbs. Quantity of water 

 discharged by the pumps daily 535,173 gallons. Temperature 



