of the Water at the United Mines, 103 



The quantity lifted being, in the dry season, about 1400 gal- 

 lons per minute, and, in the rainy season, about 2400 gallons. 

 The greatest difference in the temperature of the water is 

 when we have most to lift, and the mean temperature of the 

 whole is then at the lowest. In every instance the water 

 issuing from the south side of the level is colder than that 

 from the north side, and the water from the south lode is 

 colder than that from the middle and north lodes. The elvan 

 courses, as I have before said, are, at all seasons of the year, 

 the channels through which a considerable portion of the wa- 

 ter is conveyed into the mines, and I believe nearly all the 

 additional water in the wet season is brought in by them. 

 This water finds its way into the mines rapidly, and without 

 having passed through the lodes to the same extent as that 

 portion of the water which is always flowing, and which may 

 be considered as the permanent source of supply to the en- 

 gines. 



My remarks in reference to the manner in which the el- 

 van courses intersect the lodes, will at once shew you how 

 any water passing through them will, in every instance, 

 make its appearance on the south side of the levels, and that 

 the south lode will drain a larger portion of the water thus 

 brought into the mines than either of the others ; hence it is 

 clear that the temperature of the water depends on the time 

 which it requires to pass from its source to the different 

 parts of the mines, and also to the medium by which it is 

 conveyed. Several circumstances exist to shew that what I 

 have termed the permanent supply of water to the engines, 

 must be derived from sources at a considerable distance from 

 the mines, and that its course through the lodes is at a depth 

 from the surface little short of that at which it comes into the 

 shafts, and which varies from 200 to 260 fathoms. 



I am aware that it may be urged that, in other mines, 

 when a difference in the temperature of the water is ob- 

 served, the same causes to produce it do not exist as I have 

 described in the United Mines ; but, notwithstanding such 

 mines may not have large elvan courses running through 

 them, it will be found that other means of letting down wa- 

 ter freely do exist, such as large cross- courses, changes of 



