Mineral Deposits of Southwest Wisconsin. — Blake. 245 
smithsonite or " bone " is sent chiefly to the works of the 
Mineral Point Zinc Oxide Works, at Mineral Point, in Iowa 
county, Wisconsin, on the line of the Chicago, Milwaukee & 
St. Paul railway, and some now goes to the newly established 
works of the Lanyon Zinc Oxide and Paint Co., at Waukegan, 
on the shore of Lake Michigan, about 30 miles north of Chi- 
cago. A few shipments are made to the St. Louis works of 
Page & Crouse, and a new establishment at Dubuque, Iowa, is 
projected. The value of the best grades during the year 1892 
ranged from $18 to $24 per ton, delivered on the rail. The 
quality of even the best grades varies at different localities. 
At some, the bone is light-colored ; at others, it is more or less 
discolored by iron oxide or ocher ; manganese oxide is rare. 
Thick, solid crusts of compact and vitreous ore, like some 
obtained in England, are seldom seen. Zinc silicate is but 
rarely found. Mineralogically, the specimens are not beauti- 
ful, but they sometimes have the form of very interesting 
casts or replacements of crystals of calcite. 
Although the attention of the miners had been directed, 
before the year 1855, to the commercial value of the dry-bone 
(smithsonite), which they were then throwing away as use- 
less, it was Percival, the poet and geologist, who first effected 
a practical utilization of this ore by sending two barrels of 
it to the works of the New Jersey Zinc Co., at Newark. N. J., 
where its value was practically demonstrated.* 
Blende — " Black- Jack." 
The blende of Wisconsin is very different in its appearance 
from the ruby-red variety of the Missouri mines. It is, in- 
stead, generally of a dark color, and hence appropriately 
called "black-jack;" but this color is seemingly due not so 
much to the presence of combined iron as to organic matter. 
This is partly destroyed by heating, and the blende then be- 
comes lighter in color. The proportion of zinc in the clean 
blende compares well with that of any other localit}^, ranging 
from 60 to 64 per cent, or more. Some of the deposits yield 
*Percival, in his first Report, 1855, wrote, p. 97 : "The ores of zinc, 
although very abundant in many instances, particularly id the fiat and 
pitching sheets and in the lower openings, have never yet been turned 
to any account. There can be no doubt that they must be hereafter 
sources of profit when we consider the large and increasing demand for 
zinc, both in its metallic form and as an oxide (zinc-paint)." 
