242 RESOURCES OF CALIFORNIA. 
are those in gullies which have no water, save during a small 
part of the year. A “claim” is the mining land owned or 
held by one man or a company. 
The placer mines are again classified according to the man- 
ner in which, or the instruments with which they are wrought. 
There are sluice claims, hydranlic claims, tunnel claime, dry 
washing, dry digging, and knife claims. In 1849 and 1850, 
the main classification of the placers was into wet diggings 
and dry diggings, the former meaning mines in the bars and 
beds of rivers, and dry diggings were those in gullies and flats 
where water could be obtained only part of the year or not at 
all. That classification was made while nearly all the mining 
was done near the surface, before the great deposits of pay- 
dirt in the hills had been discovered, and before ditches, sluices, 
and the hydraulic process had been introduced. The class of 
mines then known as the “dry diggings,” and which for 
several years furnished nearly half of the gold yield of the, 
state, are now, with a few unimportant exceptions, exhausted, 
or left to the attention of the Chinamen. 
The purpose of all placer miners is not to catch all the gold 
in the dirt which they wash, but to catch the greatest possible 
quantity within a given time. It is not supposed that any 
process used in gold mining catches all the metal. Part of itis 
lost ; in some processes a considerable proportion. The general 
estimate in California is, that one-twentieth of the gold in the 
dirt which is washed is lost. Many of the particles are so 
very small as to be invisible to the naked eye, and. so light 
that their specific gravity does not avail to prevent them from 
being carried away by the water like sand. The larger pieces 
will sink to the bottom and resist the force of the water; the 
smaller the particles, the greater the danger that it will be 
borne away. Many devices have been tried to catch all the 
gold, but none have succeeded perfectly, and some which have 
caught a portion of what escaped from the ordinary modes of 
mining, have been found to cost more than their yield. The 
miner does not grieve about that which he cannot catch. He 
