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overlooked in this State, and while not large at present, bids fair to become of much greater proportions.

The article copied will be found to give a very good general idea of it.

AMERICAN “ TRIPOLI."

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BY E. O. HOVEY. Tripoli is a term which was originally applied to an infusorial earth, resembling clay or chalk in appearance, coming from the country of the same name in Northern Africa. It crumbles or powders easily between the fingers, is a little gritty to the teeth, and scratches glass when rubbed on it. This earth consists almost entirely of silica in the opal or soluble state, and is made up mainly of the siliceous skeletons of the minute animal organisms known as polycystines or radiolarians, and of the equally minute plants called diatoms. Similar deposits, frequently of great thickness, occur in many other parts of the world, notably in Barbadoes, Sicily, Calabria, Greece, and the Nicobar islands. The well-known “'Barbadoes earth" consists mostly of these siliceous skeletons, but contains, besides, a variable proportion of the calcareous shells of foraminifera. This deposit rises to heights of more than 1000 feet above the level of the sea, while that of the Nicobar islands reaches an elevation of about 2000 feet. According to Haeckel, the eminent German naturalist, there are not less than four hundred, and there may be more than five hundred, species of polycystines in the Barbadoes earth, very many of wbich “are today extant and unchanged in the radiolarian ooze of the deep Pacific ocean." In Bobemia there is a celebrated deposit of tripoli ("Polir-schiefer”), largely used as & polishing powder, which is composed almost entirely, if not entirely, of the siliceous framework of diatoms. In the United States there are great de posits of diatomaceous earth, near Richmond, Va., and Monterey, Cal., of which the former is about thirty feet thick, and extends for more than & hundred miles from north to south across the State, while the latter exceeds fifty feet in thickness and is of unkrown extent. All the beds noted above are of Tertiary age.

Tripoli is used very extensively in the form of powder as an abrasive, and forms the base for many polishing pastes and other similar preparations. The extreme fineness of the natural grain, combined with the hardness of the individual particles, composed as they are of silica, gives this substance its advantages for this purpose. It is also largely employed in mixing nitro-glycerine in the manufacture of dynamite.

Within a comparatively few years there has developed at Seneca, in the extreme southwestern corner of Missouri, a large business in the quarrying and manufacture of a rock which is called “tripoli,” for the want of a better term, and because the material, in some respects, resembles what has so long gone by that

This rock appears to have been derived from the flint of the country rock, which is a cherty lower carboniferous limestone, by some process of decomposition which has left behind a bed of very fine-grained, rather soft, porous material, which has considerable strength when cut into disks and other forms. This particular deposit is known to underlie between 80 and 100 acres of land, as a rude ellipse, with its longest diameter approximately north and south. Numerous prospect holes show that the bed is from 2 to 4 feet below the surface of the ground, and that it varies from 10 to 25 feet in thickness, with an average of about 15 feet. The main quarry of the company working these beds at preaent shows a section 18 feet thick. A well sunk in the northern part of the property gave the following section:

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The drill was lost in this soft rock at about 173 feet. The first 53 feet of the well was sunk by digging, the remainder by using a six-inch plunger drill.

Not only is the bed of tripoli everywhere underlaid by a relatively thin stratum of very stiff red clay, but it is transversed in every direction by seams one to two inches thick of the same substance. These seams and other joints divide the rock into masses which vary in size up to thirty inches or more in diameter. In color the material varies from an almost pure white, through a cream tint, to a delicate rose, depending, probably, on a difference in the small amount of iron present.

The rock is very even in texture, and is so minutely porous that it forms & most excellent natural filter. Last year ( 1893) the American Tripoli Company, which owns and operates this deposit, put on the market more than 20,000 disks, cylinders and blotters. These articles are patented.

A second and fully as important a branch of this industry is crushing the rock and grinding it into flour, for use in polishing all kinds of metals, horn, shell, etc. The company grinds the rock in a common mill, between burr stones, and sifts it tbrough two bolts of 70 and 120 mesh, similar to those used for bolting wheat flour. Last year the company sold upward of 20,000,000 pounds of this ground and bolted tripoli flour.

A portion was scraped off from a crude piece of the rock and mounted for the microscope. Examination with powers magnifying up to 450 diameters failed to show any remains of the skeletons of radiolarians or diatoms. The parlicles mere extremely minute, by far the most of them being not over 0.01 mm. (=0.0004 inch) in diameter, though an occasional grain measured 0.03 mm, across, and one was 0.05 mm. through. The particles are doubly refracting and are probably chalcedony, while the infusorial tripoli consists of opaline silica.

The credit of developing this industry is due to Mr. T. T. Luscombe, of Carthage, Mo., who is president of the American Tripoli Company. The quarries were first opened in 1872, but the great growth of the business has been within a very few years. The company received a medal and diploma award at the World's Fair, Chicago.-Scientific American,

From the following table it may be noticed that the average price received for zinc ore is quite low; this is due to the tabulation of all grades of ore under the one head of “ Zinc Ore.” To arrive at the tonnage and true price of high and low grade ores, the following additional showing is made necessary : 70,4184 tons zinc blende ore was mined, and averaged $16.52 per ton. silicate of zinc

9.32

18,7327"

The average price of lead ore is affected, for same reason as that given for low price of zinc ore, but not to any great extent.

In this table the product of each county, in both lead and zinc is shown, together with the number of employes, kind of machinery used and the number of mines operated.

TABLE I-SHOWING (BY COUNTIES) PLANT, EMPLOYES, TONNAGE AND VALUE OF PRODUCT OF LEAD AND ZIN

MINES IN MISSOURI FOR THE YEAR ENDING JUNE 30, 1894.

2 101

27 122

223

117

659

2 332 10 90 3

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Franklin. Greene Jasper Jefferson Lawrence Madison Newton St. Francois Washington Wright...

88

$34 00 1,197 63,877 35 28 $ 16 11

921 40 00 12 00 15,5534 35 32 12 34

13

6 28 52 2 2

16

1 10 25

5

22 1,832

75 293 180 296 58+ 124 10

9 12 12 151

10
15
584

15
261
53
75
618

8 5

15

37
2,416

90
554
233

371
1,202
132
15

133

10234 14,762

424 3,567 3,493

1,69074 26, 126% 1,70434

31 41 2 2

7,52074

69 14 65

58 2

1

24

100

Totals.

563

848

222

156

857

3,421

1,644

5,065

912

52,00374 89, 150/4

Machinery in use.

Employes.

Av. price per ton at inines.

Amount received for

County.

No. of mines......

Boilers

Pamps....

Crushers.

Miners....

pecting No. of men pros

........

Total .....

ore Total tons of lead

ore Total tons of zinc

ployes...

Lead ore.

Zinc ore.

Lead ore..

and zinc ores.... output of lead

ceived for year's Total amount re

Zinc ore.

$4,500 00

3,499 00 $20,996 00
520,833 45 | 1,029,342 48

16,960 00 11,052 00
125,979 42 191,724 13
104, 790 00

57,841 39 83,395 75
1,057,379 80
67,785 50

1,400 00

$4,500 00

24,495 00 1,550,175 93

28 012 00 317,703 55 104,790 00

141,237 14 1,057,379 80

57,785 50 1,400 00

38 88

14 00

37 48

• 15 00

1,949,568 56 | 1,337,910 36

3,287, 478 92

TABLE II.

This table furnishes the output of both lead and zinc ores for the past six years—1889 to 1894 inclusive.

In making a comparison it will be found that the production of zinc ore during the past year is much less than for either of the four preceding years. The decline in price is the sole cause for the falling off in production, as operators would not mine the ore at prices offered for it.

Lead ore production has increased, and the output for the past year is in excess of the amount produced in any former year. The price of lead ore has also declined, but relatively not to the extent experienced in zinc ore. One reason for the increased production this year, is that operators of lead and zinc ore mines in Southwest Missouri have allowed the zinc mines to remain idle, while they mined lead ore in preference, because it was more profitable at the prices offered.

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