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TENT HILL, COBALT. Presbyterian church tent at right.

case of one of the mines, the story is told that father and son had been out prospecting for days and were at last tired out and about to give it up, when the father lay down on the ground to rest, and finding a stone under his head, went to remove it, when to his astonishment he found it to be solid silver. Another of the mines-the Foster-was discovered as the result of trenching, i. e., removing the soil from the rock across a certain area, and examining the exposed rock surface for veins. This is an expensive method of prospecting, but in this in. stance it was worth the expense.

But if the veins are small and difficult to discover on the surface, they are 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 with these views of silver, a number of interesting questions might be asked. How did the sil

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 coloris to be found. This greenstone was at a later stage covered with another formation, called the Huronian. Through this Huronian, at a still later stage, at varicus points, there surged up in molten form a conglomerate rock known as diabase. The diabase, in cooling, left cracks or fissures; and it is these cracks that are filled with the veins of native silver. It is supposed that the silver was either strained out of the surrounding rock in its molten state or that it was deposited there by the heated waters that surged up through these fissures from below.

Now, the diabase in which the silver is found is met with practically only in the Huronian strata overlying the Keewatin rock. This Huronian rock has

been worn down in many places by the

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PART OF TRETHEWEY MINE PROPERTY ON HILL OVERLOOKING COBALT.

HUDSON BAY MINE.

One of the newer plants just starting.

action of natural forces in the course of millions of years, and on the higher ground the greenstone underlying it is once again exposed. It is supposed, therefore, that the depth of the silver veins depends on the depth of the Huronian strata in which they occur; and it is estimated that in some places, in the natural depressions filling up old valleys, the Huronian formation is perhaps 500 feet deep, and the mines at such points may be supposed to run to that depth also.

This whole question is, however, only a matter of theory, and time alone will tell definitely whether these theories are correct. It is worth noting, however, that

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 neighboring towns are doubly so. Hither as by a magnet are drawn adventurous spirits from almost every quarter of the London, Yankee speculators from "down globe-Englishmen from the heart of East," miners from California and Australia, German Jews, Syrians, Chinese, Italian navvies, Frenchmen from the lumber camps, Canadian and American rich millionaires, school teachers and tourists, broken-down merchants and students, all striving directly or indirectly to gain some share of the newfound wealth.

The public square in Cobalt is the gathering place for most of this floating population, and the scene presented from the steps of the banks or the theater on either side on a summer evening is inter

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the Huronian strata at other points far-esting in the extreme. The picturesque,

ther 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 not exist in this country, Cobalt would

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Predict Next Year's Weather

By John Elfreth Watkins

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CIENTISTS at Washington feel almost confident of being able to predict, before long perhaps in a year whether an approaching season will be abnormally hot or cold, wet or dry. Ability to forecast weather several months ahead, has been claimed by no end of mystics and charlatans; and the term "long-range forecasting" had in consequence fallen into disrepute long before that distinguished physicist, Prof. S. P. Langley, late Secretary of the Smithsonian Institution, commenced work upon the problem by methods which are the purest of pure science.

In the shadow of the Smithsonian towers, in Washington, is a group of white frame buildings known as the United States Astrophysical Observatory. This unique institution, conceived, developed, and directed by Professor Langley, is where the new system of long-range

forecasts is being developed. This longrange weather forecast possibility will appear more clear to you if I first repeat, as nearly as I can recall, what was told me, by way of introduction to a description of the full modus operandi, by Mr. C. G. Abbott, now in charge of the Astrophysical Observatory, where he has been Professor Langley's aid for the past ten years.

The earth is a body hanging out in space and receiving rays from the sunsome visible and some invisible, the latter approaching in wave-length our electric rays used in wireless telegraphy. Now, the earth not only receives this energy from the sun, but radiates it back into space. If the sun should grow hotter, the earth would have to grow hotter also to keep a balance between radiation received and sent out. If the sun's radiation of this energy, or heat, upon earth is measured from day to day, and is found to fall off 10 per cent, say to-day, a week or more will be required before the consequent fall of temperature will be felt in

PYRHELIOMETER HOUSE, MOUNT WILSON OBSERVATORY.

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 possible for those cognizant of the conditions to pre

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MAIN BUILDING, MOUNT WEATHER OBSERVATORY.

dict whether the approaching season will be hot or cold, wet or dry.

The instrument playing the chief rôle in this work is the "bolometer"-a wonderful electric thermometer invented by Professor Langley, and so delicately wrought that it registers variations of the sun's radiation in millionths of a degree. The bolometer stands in a dark room, and the sunbeams are thrown into it after being first caught outside the building by a traveling mirror which follows the sun by clockwork and is always in a position to reflect the beam through a prism in the dark room and then from one reflector to another, into the bolometer. This instrument registers the sunbeam's changes in radiation by means of a magnetic needle swinging somewhat like that of a compass.

Another delicate instrument-the "pyrheliometer"-is employed for measuring the rate at which the sun's heat is received at the earth's surface. You may have heard that a bucket of water would be warmed by the sun much faster on a mountain top than at the brink of the sea, because upon the mountain there is less air between the bucket and the sun to screen off the latter's rays from the bucket. Since all sun rays, whether ab

sorbed at the earth's surface or in the screen of air above it, alter climate and vegetation, Mr. Abbott considers it important to determine how much of this radiation is thus lost in the air. This amount is found to vary greatly at different times, because of clouds, invisible moisture, dust, or smoke in the air. In autumn the air is generally more transparent than in spring and summer; but it sometimes happens that whole years are found by these delicate measurements to differ from others in the transparency of the air. It was discovered at the Observatory that during 1901 and 1902 the air allowed much more heat to pass through it than during the first eight months of 1903, after which the transparency increased to about its former state. It is thought that this change was caused by the great volcanic eruption of Mont Pelée, which sent thousands of tons of dust into the air.

Speaking generally, it is found that the sun's beam, in passing entirely through our atmosphere, to sea-level, loses about half its heat in the air; but most of this loss is made up to us on a clear day by the light coming from all parts of the sky. Clouds, on the other hand, reflect away about three-fourths of the sunlight

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