rict is in the vicinity of
Nevada City, which has fifteen mills, and Grass Valley, five miles
distant, has seventeen. The great Allison mine, which has the richest
lode in the state, is in Grass Valley.

The quartz mines here are much troubled with water, and during the
winter of 1860-61, many of the mills were compelled to stop for weeks
until the shafts could be drained by steam engines, after having been
filled by a long and heavy rain. The annual gold yield of Grass Valley
has been estimated at four millions of dollars. North San Juan has the
finest hydraulic claims, and Sweetland the largest tail-sluices. The
Eureka Lake Ditch Company has more ditching and water than any other
company in the state. Their main ditch is seventy-five miles long, and
there are one hundred and ninety miles of branches, making a total of
two hundred and sixty-five miles, which have cost nine hundred thousand
dollars. The daily sale of water is six thousand inches, with a weekly
income of six thousand dollars. The principal mining towns are Nevada,
Grass Valley, North San Juan, Rough and Ready, Orleans Flat, Moore's
Flat and Humbug City.

INDEX.

PAGES.

Chief Industry 3

Metals obtained 3

Gold Mines 3

Placer Mines 5

The Sluice 7

Amalgamation 9

Cleaning up 11

Riffle-Bars 12

Double Sluices 13

Rock-Sluices 13

Hydraulic Mining 14

Blasting 16

Tail-Sluice 16

Tunnel-Sluice 17

Ground Sluice 17

Long Tom 17

Cradle 18

Pan 20

Dry Washing 22

Dry Digging 22

Puddling-Box 22

Quicksilver-Machine 23

Tunnel-Mining 23

Shafts 24

River-Mining 24

Beach-Mining 26

Mining-Ditches 27

Prospecting 27

Quartz-Mining 27

Distribution of Gold in Quartz 28

Prospecting Quartz