198 JOURNAL OF THE PLYMOUTH INSTITUTION. 
tion simply for the purpose of collecting water where obtainable, 
and conveying and distributing it, over districts where it is required 
for metallurgical operations. One company alone, the Eureka, has 
more than 200 miles of ditches, or water-courses, distributing 
nearly 83 million cubic feet of water in 24 hours, or 237,165 
tons. The cost of the plant amounted to upwards of £250,000. 
The greater portion of this water is consumed in breakmg down 
old river beds cemented together by lime, mud, &c., in order to the 
separation of the gold contained therein. In a single work as much 
as 4,000 to 5,000 tons of gravel are broken down in 24 hours, and 
profitable results have been obtained, although the “dirt” produced 
only 3 cents, or 14d. worth of gold per ton (15 cubic feet). The 
rent paid for the water used, amounted to $70, or £14 per day— 
£4,200 per annum. In supplying water for such purposes the 
Eureka Company has spent upwards of £40,000 per annum, and 
obtained a net revenue of profit, after paying all expenses, of 
upwards of £30,000. 
It appears that the cost of handling a eubic yard, or nearly two 
tons, is about } or 4 of a penny per ton. Throughout Devon 
and Cornwall we may see very extensive arrangements for the 
utilization of the mechanical properties of water, but as yet 
nothing to be compared with those erected within a very few years 
in the modern mining districts of California and Nevada. We 
need not go far from Plymouth to see examples of the utilization 
of water. At Devon Great Consols are two very fine water-wheels 
worked by water taken out of the Tamar for the purpose of driving 
a portion of the river to the top of the hill, where it is used in a 
variety of ways which will serve to illustrate the properties and 
uses of water. 
The portion of the river which passes over the wheels imme- 
diately returns to the stream, and the value of the work done by 
it is sufficient to allow of the mine paying the Duchy £500 per 
annum for being allowed to take the water out at one point and to 
restore it at another. The portion of the water thrown to the top 
of the hill by plunger pumps through large cast-iron pipes is dis- 
charged into a large reservoir, whence it flows over a water-wheel 
employed in driving the machinery of a foundry and smith’s shop. 
Another water-wheel, driven by the same water, is used for conveying 
the men by man-engine some 300 fathoms, or 1,800 feet, in depth 
to their work, and in bringing them back again when their day’s 
