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ver come to appear here in this form? How deep do the veins run ? Etc. The answer to such questions involves a good deal of technical explanation. In general, however, it may

be pointed out that there are three classes of rock formation involved. At certain points an old rock formation called the Keewatin — or “greenstone,” from its color

is to be found. This Tent Hill, COBALT.

greenstone was at a later Presbyterian church tent at right.

stage covered with an

other formation, called case of one of the mines, the story is told the Huronian. Through this Huronian, at that father and son had been out pros- a still later stage, at varicus points, there pecting for days and were at last tired surged up in molten form a conglomerate out and about to give it up, when the rock known as diabase. The diabase, in father lay down on the ground to rest, cooling, left cracks or fissures; and it is and finding a stone under his head, went these cracks that are filled with the veins to remove it, when to his astonishment he of native silver. It is supposed that the found it to be solid silver. Another of silver was either strained out of the surthe mines—the Foster-was discovered rounding rock in its molten state or that as the result of trenching, i. e., removing it was deposited there by the heated the soil from the rock across a certain waters that surged up through these fisarea, and examining the exposed rock sures from below. surface for veins. This is an expensive Now, the diabase in which the silver method of prospecting, but in this in- is found is met with practically only in .stance it was worth the expense.

the Huronian strata overlying the KeeBut if the veins are small and difficult watin rock. This Huronian rock has to discover on the surface, they are been worn down in many places by the nevertheless exceedingly rich, for in most cases they are practically solid silver, and the ore in some cases yields as much as $2,000 to $3,000 per ton. It is not an uncommon thing for nuggets of solid silver to be taken out weighing from 300 to 600 lbs. The ore itself is packed in sacks, shipped," and sold in three grades according to its richness. In connection

connection with these views of silver, a number of interesting questions might be asked. How did the sil- Part of TrethEWEY MINE PROPERTY ON Hill OVERLOOKING COBALT.

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still be remarkable for its valuable deposits of smaltite—an arsenide of cobalt, nickel, and iron—from which cobalt is obtained. The uses to which cobalt is put have thus far been limited; but if Edison, who is operating a cobalt mine on the Montreal river, should succeed in extending its use, as seems probable, in the construction of electrical storage batteries, then the value of these mining properties will be immeasurably increased.

But if the mines in the Cobalt district

are interesting, Cobalt itself and the HUDSON BAY MINE.

neighboring towns are doubly so. Hither

as by a magnet are drawn adventurous action of natural forces in the course of spirits from almost every quarter of the millions of years, and on the higher London, Yankee speculators from “down

globe-Englishmen from the heart of ground the greenstone underlying it is

East,” miners from California and Ausonce again exposed. It is supposed, tralia, German Jews, Syrians, Chinese, therefore, that the depth of the silver Italian navvies, Frenchmen from the veins depends on the depth of the Huronian strata in which they occur; and it is

lumber camps, Canadian and American

tourists, broken-down merchants and estimated that in some places, in the rich millionaires, school teachers and natural depressions filling up old valleys, students, all striving directly or indithe Huronian formation is perhaps 500 students, all striving directly or indifeet deep, and the mines at such points rectly to gain some share of the new

found wealth. may be supposed to run to that depth

The public square in Cobalt is the also.

This whole question is, however, only gathering place for most of this floating a matter of theory, and time alone will population, and the scene presented from tell definitely whether these theories are correct. It is worth noting, however, that esting in the extreme. The picturesque,

either side on a summer evening is interthe Huronian strata at other points farther north and south have not been found to contain silver in any quantity; and the only explanation that can be given at present, is that the small district some six or eight miles square in which Cobalt is situated was left undisturbed by the great forces and movements of nature that agitated the surrounding areas and prevented the silver deposits from being made.

The process of mining the ore varies with different veins. Sometimes it is carried on by means of open trenching, no shafts being put down. But in most cases shafts are sunk either in the hillsides or perpendicularly, according to the position of the vein. The La Rose mine has already reached a depth of 250 feet, while the Trethewey mine has gone down only about 100 feet. Even if such rich veins of silver did

Silver VEIN AND Discovery Post, TreTHEWEY MINE. not exist in this country, Cobalt would Slabs worth as high as $500 have been taken from this vein.

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narrow street, on the one hand, leads to shelter of the lumbermen's and miners' the French quarter, and through it a reading room, is an open-air shooting crowd is constantly coming and going. gallery; and on the rising ground in Here, at the entrance to another side front of the offices and shops at the turn street, is a quick-lunch wagon which is in the street, an evangelist is preaching being liberally patronized. In another to another crowd. The whole scene is corner of the square, a patent medicine characteristic of Cobalt and the north vendor, with torch and stand, is doing country, and is such as one would find his utmost to attract a crowd. Here, only in a typical northern mining or lumagain, at this side of the square, in the bering town.

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Predict Next Year's Weather

By John Elfreth Watkins

CIENTISTS at Wash- forecasts is being developed. This longington feel almost con- range weather forecast possibility will fident of being able to appear more clear to you if I first predict, before long repeat, as nearly as I can recall, what perhaps in a year was told me, by way of introduction whether an approaching to a description of the full modus operseason will be abnormal- andi, by Mr. C. G. Abbott, now in charge ly hot or cold, wet or of the Astrophysical Observatory, where

dry. Ability to forecast he has been Professor Langley's aid for weather several months ahead, has been the past ten years. claimed by no end of mystics and char- The earth is a body hanging out in latans; and the term "long-range fore

space and receiving rays from the suncasting" had in consequence fallen into

some visible and some invisible, the latter disrepute long before that distinguished approaching in wave-length our electric physicist, Prof. S. P. Langley, late Sec- rays used in wireless telegraphy. Now, retary of the Smithsonian Institution, the earth not only receives this energy commenced work upon the problem by from the sun, but radiates it back into methods which are the purest of pure space. If the sun should grow hotter, science.

the earth would have to grow hotter also In the shadow of the Smithsonian

to keep a balance between radiation retowers, in Washington, is a group of white ceived and sent out. If the sun's radiaframe buildings known as the United tion of this energy, or heat, upon earth States Astrophysical Observatory. This is measured from day to day, and is found unique institution, conceived, developed, to fall off 10 per cent, say to-day, a week and directed by Professor Langley, is or more will be required before the conwhere the new system of long-range sequent fall of temperature will be felt in

our climate. Then would follow what we should call a "cold September." The sun and earth being such tremendous bodies, the observers of the phenomena feel justified in supposing that the cold spell is likely to continue for some time. In fact, a variation in the sun's radiation has been found thus far to occur only two or three times a year. Hence, when such a change is definitely established, it will be pos

sible for those cognizant PYRHELIOMETER HOUSE, MOUNT Wilson OBSERVATORY,

of the conditions to pre

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MAIN BUILDING, MOUNT WEATHER OBSERVATORY.

dict whether the approaching season will sorbed at the earth's surface or in the be hot or cold, wet or dry.

screen of air above it, alter climate and The instrument playing the chief rôle vegetation, Mr. Abbott considers it imin this work is the "bolometer”—a won- portant to determine how much of this derful electric thermometer invented by radiation is thus lost in the air. This Professor Langley, and so delicately amount is found to vary greatly at difwrought that it registers variations of the ferent times, because of clouds, invisible sun's radiation in millionths of a degree. moisture, dust, or smoke in the air. In The bolometer stands in a dark room, autumn the air is generally more transand the sunbeams are thrown into it after parent than in spring and summer; but it being first caught outside the building by sometimes happens that whole years are a traveling mirror which follows the sun found by these delicate measurements to by clockwork and is always in a posi- differ from others in the transparency of tion to reflect the beam through a prism the air. It was discovered at the Observain the dark room and then from one re- tory that during 1901 and 1902 the air flector to another, into the bolometer. allowed much more heat to pass through This instrument registers the sunbeam's it than during the first eight months of changes in radiation by means of a mag- 1903, after which the transparency innetic needle swinging somewhat like that creased to about its former state. It is of a compass.

thought that this change was caused by Another delicate instrument—the "pyr- the great volcanic eruption of Mont Peheliometer”—is employed for measuring lée, which sent thousands of tons of dust the rate at which the sun's heat is re- into the air. ceived at the earth's surface. You may

Speaking generally, it is found that the have heard that a bucket of water would sun's beam, in passing entirely through be warmed by the sun much faster on a our atmosphere, to sea-level, loses about mountain top than at the brink of the half its heat in the air; but most of this sea, because upon the mountain there is loss is made up to us on a clear day by less air between the bucket and the sun the light coming from all parts of the to screen off the latter's rays from the sky. Clouds, on the other hand, reflect bucket. Since all sun rays, whether ab- away about three-fourths of the sunlight

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