HYDRAULIC MINING. 61 
adjacent to the rivers “dry diggings.” As localities of this kind could not 
furnish room for the many thousands who came to California, search began 
to be made on higher ground and away from the rivers, and quartz mines 
were also opened at a very early period in the history of the country, the 
outcrops of many of the veins being very conspicuous. The diggings having 
gradually become extended to the flats above the rivers, and to higher 
ground, where the gravel was much less rich than it had been in the river 
beds themselves, so that much larger quantities of material had to be handled 
in order to procure the same amount of gold, the necessity for improvement 
in the system of attacking the gravel became apparent. This led to the 
invention of the so-called “hydraulic method” of mining, which dates from 
the year 1852, and is to be credited to Edward E. Matteson, a native of Ster- 
ling, Connecticut, and which as at present operated, with machinery and 
methods greatly improved over those at first used, is of the highest value to 
the State of California. 
As has been explained, the sluice is a contrivance by means of which an 
almost unlimited amount of material may be washed; it is only necessary to 
enlarge its size, and increase its length, giving it at the same time a propor- 
tionate grade. It is a piece of machinery which requires almost no looking 
after while in operation. After having run for a certain length of time, which 
may be several weeks or even months, a “cleaning up” takes place, the object 
of which is to obtain the amalgam which has become lodged between the 
rifles. After this has been done, the riffles are put back, those which are 
worn out being replaced with new ones, and the work goes on as before. 
Such being the case, it is evident that the principal expense in washing with 
the aid of the sluice will be in connection with getting the material into the 
head of the sluice. In the early days, gravel was often taken to the rocker 
on men’s backs. Besides, the gravel where it occurs in heavy masses is usu- 
ally more or less compacted together, so that it would have to be loosened 
with a pick, before it could be shovelled up to be carried off. This loosen- 
ing, and the transportation to the head of the sluice, as well, is effected with 
great rapidity, and at a small expense, considering the work done, by means 
of the so-called “hydraulic method” of mining, the principle of which is 
exceedingly simple. It consists in throwing one or more jets of water, 
issuing from a pipe with great velocity, against the face of the gravel bank, 
which water in the first place loosens the gravel, and then washes it down 
into the sluice. The force with which the stream strikes the gravel is 
