June 29,1872.J 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
1053 
■with iron the well-known pigment Prussian blue, by 
means of which the design is traced upon the paper. 
The apparatus is very simple and easy of explanation. 
A steel plate is covered in the first place with a coating 
of varnish, and upon this is scratched with a steel point 
any writing or design it is desired to copy ; as the steel 
point has removed the varnish where it has touched the 
plate, the writing is of course formed of bright metal 
•upon a varnished ground. If a design or autograph 
letter is to be copied upon the steel plate by photo¬ 
graphy, the metal surface is in this case coated with a 
solution of gelatine and bichromate, and then printed 
under a positive cliche ; on washing, there will remain, 
in the same way as before, the writing or design in 
bright metal upon a ground of bichromated gelatine. 
For printing, an ordinary letter-copying press is em¬ 
ployed, the bed of which is insulated from the upper 
plate; so that if the two wires from an electric battery 
are connected, the one to the top and the other to the 
bottom of the machine, no current could pass until the 
upper and lower plates of the press were screwed to¬ 
gether and thus brought into contact. Three or four 
sheets of thin copying paper are now impregnated with 
a, solution of prussiate of potash, and while still moist 
tlie steel plate bearing the writing or design is placed 
upon them, and the whole put into the press. The wires 
of a battery are attached in the manner indicated, and 
the press screwed down. A current of electricity then 
passes from the upper to the lower plate of the press 
and through the moistened paper, decomposing the 
prussiate contained therein ; the electricity can, however, 
pass only when there is a bright metal surface; and this 
occurs, as we have seen, only where the design in bright 
metal appears (where the steel plate is not covered with 
varnish); and in these places, some of the metallic iron 
being dissolved, there is formed prussiate of iron, or, in 
other words, the blue pigment known as Prussian blue. 
Consequently, the moist sheets of copying paper, when 
the electric action is set up, are stained with a reproduc¬ 
tion of the design upon the metal plate; and as many 
limes as the operation is repeated, so often will a batch 
■of three or four copies be produced. As thirty seconds 
or a minute is sufficient for each operation, copies can in 
this way be easily obtained at the rate of a hundred per 
Four. 
The patent is, we believe, the property of Messrs. 
Waterlow and Sons, who propose at once to offer it to 
the public ; for in such places as the counting-house and 
•engineer’s office the apparatus will be invaluable. The 
•electro-chemical copying press, as we believe it is termed, 
forms one more excellent example of science serving as 
.handmaiden in our everyday life .—Photographic Journal. 
QUICKSILVER. * 
The long-prevailing high price of quicksilver has ex¬ 
ercised an important influence on our mining interests, 
and the importance of obtaining it at low rates will be 
evident to all, except producers. In the production of 
gold and silver bullion quicksilver is an indispensable 
requisite, and without it our mines could not be deve¬ 
loped, unless the ingenuity of our people could devise 
some suitable substitute not now known. The produc¬ 
tion of this necessary article at the cheapest possible 
rate is a matter of great interest to our mining popula¬ 
tion ; and the many mines of this metal in California, by 
proper and economical working, with suitable appliances, 
•and without combinations to keep up rates, should be 
.able to produce and sell it at a much more reasonable 
price than present quotations. A low price for quick¬ 
silver would cause an increase in consumption, and of 
course, larger sales, requiring a greater production. It 
* This article, taken from an American source, appeared 
•in the Wming Journal for June 15th, 1872. We reprint it as 
containing matter likely to be of interest to our readers. 
is an absolute necessity for the purposes for which it is 
mainly used, and for amalgamating particularly, where 
it is now used with a sparing hand, a more plentiful sup¬ 
ply would be a material benefit. 
The amount of quicksilver which the various mines of 
the world are capable of producing is very large, much 
larger,. in fact, than is demanded for any purposes to 
which it is at present applied, and the only reason why 
it is held so high is that a few parties have control of 
the supply of the world. The Almaden Mine, in Spain, 
discovered in 1497, yielded for 250 years from 550,000 to 
650,000 lb. per annum. In 1750, when the Huanca- 
velica Mine of Peru caved in, and the supply from that 
source was temporarily cut off, the Almaden increased 
its production to about 2,016,000 lb. per annum, and 
has continued to yield that amount ever since. The 
Santa Barbara Mine, of Huancavelica, which had up to 
1867 produced 80,000,000 dollars’ worth of quicksilver, is 
now abandoned. The reasons given are its distance 
from sea-board, low grade of ores, and scarcity 7 of fuel, 
being unable from these causes to make any profit in 
competition with the other great mines of the world. 
The Idria Mine, in Transylvania, is another of the im¬ 
portant mines of the world, and its production is from 
600 to 800 flasks per month. The ores are of a low 
grade. This mine is under lease from the Government. 
California, among its numerous mineral advantages, 
possesses the broadest fields of this necessary article in 
the world, and by far the most prolific of its mines is the 
well-known New Almaden, in Santa Clara County. As 
it may be interesting to know the amount produced from 
this mine yearly, as the representative one of California, 
the following figures will show it, in flasks, premising 
that the flasks contain 76£ lb. of quicksilver. In 
1851 the number of flasks produced was 23,875; in 
1852, 19,921; in 1853, 18,035; in 1854, 26,325; in 
1855, 31,860; in 1856, 28,183; in 1857, 26,002; 
from July, 1857, to October, 1858, 39,935. From 
that time to February, 1861, the mine was closed 
by injunction. From February, 1861, to January, 1862, 
it produced 34,765 flasks; in 1862, 40,391; in 1863, 
19,564; in 1864, 46,216; in 1865, 47,194; in 1866, 
35,150; in 1867, 24,461; in 1868, 25,628; in 1869, 
16,898; in 1870, 14,000; and in 1871, 18,763 flasks. 
Total up to January, 1872, 537,176 flasks, each contain¬ 
ing 76£ lb. of quicksilver. 
The New Idria Mine, in Fresno County, produced in 
1866, 6045 flasks; in 1867, 11,500; in 1868, 12,300; in 
1869, 10,450 ; in 1870, 10,000 ; and in 1871, 9227 flasks. 
The Redington Mine, near Knoxville, Lake County, 
produced in 1866, 2980 flasks; in 1867, 7145 ; in 1868, 
8700; in 1869, 5000; in 1870, 4546; in 1871, 2128 flasks. 
Among the other mines whose products go to swell the 
gross amount are the Guadalupe, in Santa Clara County, 
owned in Baltimore, Md.; the Josephine, in San Luis 
Obispo County, owned by Barren and Co.; the Enri- 
quita, owned by the Almaden, and the Bautista, owned 
by the Almaden, and now idle, both in Santa Clara 
County; the Pioneer is in Napa County, the Whitton is 
in Napa County, and there is one at Oakville. The 
Vallejo Mine is in Solano County; the Manhattan or 
Knox and Osborne Mine is three miles from Knoxville, 
in Lake County; the California is in Yolo, and there are 
several in Pope Valley, near Napa ; the Abbot Mine is 
in Lake County; Excelsior in same count} 7 . There are 
several in Monterey, one of which is called the Pennsyl¬ 
vania," which produced a small quantity, and one owned 
by M‘Garrahan not now being worked. There is one at 
Mount Diablo, Contra Costa County, which produced a 
small quantity, but is now in litigation. An occasional 
flask comes from the San Luis Obispo Mines. The 
Riotte and Lockhart Mine is at St. Helena, Napa County. 
The Phoenix, in Pope Valley, Napa County, produced in 
1870, from a partial working only, 763 flasks. There is 
also a mine in San Bernardino County, and several 
recent discoveries in Napa and Lake Counties, and a 
