respecting the Temperature of Mines. 45 



but as some deep mines have been set to work since he made 

 his experiments, the average quantity is now probably greater. 

 It appears, on making a comparison of the depth of the water 

 at tlie time the foregoing temperature was ascertained, with 

 his calculations, tliat the quantity discharged was equal to 

 1400 cubic feet per minute, or about 60,000 tuns per day." 



" The great adit is divided into three principal branches, 

 the first of which unites with it at about a mile from its mouth, 

 and communicates with the United and the Consolidated 

 Mines, Huel Squire, Ting-Tang, Huel Maid, and South 

 Huel Jewel ; the average depth of which mines seems to be 

 about 150 to 160 fathoms. The temperature of the water in 

 this branch, near the junction, and about 1^ mile from the 

 mines which principally supply it with water, was 73*5° about 

 the end of last month, when this and the following observa- 

 tions were made. At nearly a mile further on, the great adit 

 is divided into two branches; one of them receives the water 

 from Poldice, Huel Unity, Huel Unity- Wood, Huel Damsel, 

 Huel Pink, Rose Lobby, Huel Hope, Huel Gorland, Hue] 

 Jewel, and Huel Clinton ; the average depth of which is per- 

 haps from 110 to 120 fathoms, and the temperature of the 

 water in the branch, at about a mile from the principal mines 

 above named, was 66'5^. The other branch is connected with 

 Treskerby, Huel Chance, Chacewater, North Downs, Creg- 

 braws, Huel Boys, Cardrew, and a few smaller mines ; their 

 average depth may be estimated at 100 to 110 fathoms, and 

 the temperature of the water in the atlit, about 3^ miles from 

 the mines, was 65°. I have not ascertained the quantity of 

 water discharged by each of these branches ; but it is evident 

 they carry off, not only the water pumped from the various 

 levels of the respective mines, but also that which is drained 

 from the strata under which they pass, and which is from 30 

 to 50, and in some places from 60 to 70 fathoms in thick- 

 ness." 



" The temperature of the water in the adit is therefore 

 even more considei'able than might be expected; and the dif- 

 ference observed in the branches may be attributed to the 

 relative dejiths of the mines witli which they are connected, 

 and to m;niy of those communicating with the two last-men- 

 tioned branches, being stojjped, or i)artly full of water." 



" I have mentioned Uiat tlie water flows into cisterns at dif- 

 ferent levels in mines, being partly or entirely i-etained by the 

 rock on which it rests ; but generally, from the strata being 

 more or less jiorous, some of the water sinks through it, and 

 may eitlicr mix with an inferior portion before it (lows into 

 the levels, or it sometimes descends in numerous drops or smnll 



streamlets 



