a pound in working one hundred tons of quartz; in twenty-one the s than a pound in working ten tons; and in six the loss is over one working ten tons. The lowest loss is seven pounds in working one tons, and the yield of the rock there is reported to be $25 per ton, and st is one hundred and ninety-eight pounds for one thousand tons; and se the rock is reported to yield $17 14 per ton. The general rule is, that the higher the yield of gold, the greater the loss of quicksilver per

1,0

1,0

1,0

2,0

The amalgamating apparatus in the mills marked with the asterisk is given below. ¡C. copper plate. C. & A. copper plate and arrastra. || W. & S. water and steam. A. arra

In numbers 5, 6, 11, 12, 14, 25, 30, and 40 the average yield is obta dividing the sum of two figures given by Mr. Rémond. For insta average yield of mine No. 5 is given above as $32 50, whereas Mr. says the yield is from $25 to $40. In the same manner the cost of ex in No. 37 is given at $4 37, whereas Mr. Rémond says it is from $27 Mines Nos. 59 and 70 yield coarse gold, which is taken from the ro pounding it in a hand-mortar.

In mill No. 11 Hungarian pans are used, and in No. 12 Hungarian an arrastra; in No. 13, Patterson's pans and separators; in No. 14 plates and amalgamating pans; in No. 15, Salmon's amalgamator and separator; in No. 23, copper plates, an arrastra, a Beath's grinder, ar mon's concentrator; Nos. 26 and 37, copper plates and blankets; in a centrifugal grinder, a Ryerson's pulverizer, a super-heated steam a and a shaking table; in No. 28, shaking pans and a Chili mill; in copper plates, shaking pans, and an arrastra; in No. 30, cast-iron ba No. 31, copper plates and a shaking pan; in No. 32, copper plates, a and a shaking table; in No. 34, an Ambler's concentrator, a shaking t arrastras; in No. 35, copper plates and a Beath's amalgamator; in Varney's pans and a concentrator; in Nos. 66 and 67, copper plates and pans; in No. 71, copper plates, a Farrand's amalgamator, and a settler 73 Varney's pans and a settler, and in No. 82, copper plates, shakin and an arrastra.

It appears that the average thickness of 21 lodes is from 1 to 12 inclusive; in 20, from 13 to 24 inches, inclusive; of 9, from 25 to 30

Cost of roads.

; of 10, from 37 to 4 inches, inclusive; of 9, from 5 to 10 feet includ of 2; over 10 feet.

ines the average yield is under $10 per ton; in 22 it is between $10 inclusive; in 14 it is between $20 and $29, inclusive; in 14 it is be30 and $49, inclusive; in 3 it is between $50 and $69, inclusive, and in er $70. Only one mine has a yield as low as $4; three have a yield of $8, and 1 of $9.

cost of extraction per ton depends, to a considerable extent, upon the s of the vein, or, rather, of the pay-rock in the vein. In mine No. 48 is only two inches thick, and it costs $60 to get out a ton of ore, while 2 it costs only 50 cents to take out a ton of rock from a vein 15 feet wide. e the cost of extraction was under $1; in 8, between $1 and $1.90 inin 14, between $2 and $2 90, inclusive; in 9, between $3 and $3 90, ; in 9, between $4 and $4 90, inclusive; in 7, between $5 and $9 90, , and in 7, $10 or more.

mines there is no cost of transportation of ore to mill, the extraction that expense; in 23 mines the cost is less than 90 cents; in 7 mines ween $1 and $1 90, inclusive; in 6 it is $2 or more.

ill the cost of treatment is 75 cents; in 14 mills it is from $1 to $1 90, ; in 19 it is from $2 to $2 90, inclusive; in 9 it is from $3 to $390, , and in 9 it is $4 or more. The richer the rock, as a general rule, the pensive the treatment. The quartz of mine No. 48, yielding $180 to costs $7 for treatment.

emills visited by Mr. Rémond in 1865, 38 were not running, 25 were 2 were ruined, and 2 were unfinished. Of those not running, some ading idle for want of water, others had exhausted the pay-rock within 1 were preparing for further explorations, and the owners of a third l no expectation of resuming work, having found it unprofitable, but sell or intended to move their machinery.

ost of each of 11 mills was under $2,900; of 20 mills it was between and $3,900, inclusive; of 14 it was between $5,000 and $9,000, inand of 14 it was $10,000 or more.

umber of stamps in 10 mills was 4 or less; in 22 mills, between 5 and ive; in 20 mills, between 10 and 14, inclusive; in 10 mills, 15 or more. ower in 52 mills is water; in 11 mills, steam; in 3, water and steam. mills copper plates were used alone for amalgamating, (outside of the in 3 the arrastra was used alone; in 7, copper plates and arrastra ; 5, other devices, with or without copper plates or arrastras.

mills the roads cost less than $1,000 for each; at 12 mills, between nd $1,900, inclusive; at 4 mills, between $2,000 and $2,500, inclusive; 500; and at 15, nothing.

ch of 21 mills the ditches and flumes cost less than $1,000; at 13 mills was between $1,000 and $1,900, inclusive; at 3, between $2,000 and nclusive; at 3, $4,000 or more; and at 14, nothing.

ounty assessor of Nevada county, California, reported the statistics of z mines and mills of Grass valley and Nevada for the year ending 1, 1866, as follows: