Jan. 1, 1805.] THE TECHNOLOGIST. 



AND THE MANNER OF WORKING THEM. 255 



loosened, violently rolled together, and cleansed from any adhering par- 

 ticles of gold ; while the fine sand and clay are carried off by the water. 

 In this manner hundreds of tons of earth and gravel may be removed, 

 and all the gold which they contain liberated and secured, with greater 

 ease and expedition than ten tons could be excavated and washed in the 

 old way. All the earth and gravel of a deposit is moved, washed, and 

 carried off through long sluices, by the water, leaving the gold behind. 

 Square acres of earth on the hill sides may thus be swept away into the 

 hollows, without the aid of a pick or a shovel in excavation. Water 

 performs all the labour, moving and washing the earth, in one operation ; 

 while in excavating by hand, the two processes are of necessity entirely 

 distinct. The value of this method, and the yield of gold by it, as com- 

 pared with the older one, can hardly be estimated. The water acts con- 

 stantly, with uniform effect, and can be brought to bear upon almost 

 any point, where it would be difficult for men to work. It is especially 

 effective in a region covered by trees, where the tangled roots would 

 greatly retard the labour of workmen. In such places, the stream of 

 water washes out the earth from below, and tree after tree falls before 

 the current, any gold which may have adhered to the roots being washed 

 away. With a pressure of sixty feet, and a pipe of from one and a half 

 to two inches aperture, over a thousand bushels of earth can be washed 

 out from a bank in a day. Earth which contains only one twenty-fifth 

 part of a grain of gold, equal to one-fifth of a cent in value to the 

 bushel, which will pay the expense of washing in the old way, gives 

 enormous profits by the new process. To wash successfully in this way 

 requires a plentiful supply of water, at an elevation of from fifty to 

 ninety feet above the bed-rock, and a rapid slope or descent from the 

 base of the bank of earth to be washed, so that the waste water will run 

 off through the sluices, bearing with it gravel, sand, and the suspended 

 clay." 



The above description and the added details are copied from a re- 

 port on the gold mines of Georgia, by Mr. William P. Blake, who has 

 .carefully studied this method of mining in California, and by whose 

 recommendation it has been introduced into the Southern States. He 

 states that in the case of a deposit in North Carolina, where ten men 

 Avere required, for thirty-five days, to dig the earth with pick and shovel 

 and wash it in sluices, two men, with a single jet of water, would accom- 

 plish the same work in a week. The great economy of this method is 

 manifest from the fact that many old deposits in the river beds, the 

 gravel of w T hich had been already washed by hand, have been again 

 washed with profit by the hydraulic process. He tells us that in Califor- 

 nia the whole art of working the diluvial gold deposits was revolu- 

 tionised by this new method. The auriferous earth, lying on hills, and 

 at some distance above the level of the water-courses, would, in the 

 ordinary methods, be excavated by hand and brought to the water ; 

 but by the present system, the water is brought by aqueducts to the gold 



vol. v. g G 



