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strong wind from the west," says Mr. Dwight, "drove us to shelter behind a pile of stones some four feet high, which former visitors had erected as a screen. Behind this we crouched for some time, resting and viewing the gorges below. Presently one of the party arose to a standing position, and the instant his head and shoulders were elevated above the protecting line of wall, a hissing sound was heard by all of us. Our friend, with a possible suspicion of snakes, turned about in a bewildered manner to ascertain whence the noise came, and in a moment exclaimed, 'Why, it is me!" His hair stood out, and the gold spectacles he wore, about which there was doubtless some small amount of steel, crackled. At first we were disposed to laugh heartily at his experience, but, as one by one we rose, (there were four of us,) and encountered the same phenomena, we thought best to beat a hasty retreat from a spot which might prove dangerous, and discuss the theory on a lower plane. Each of us experienced the sensation the moment we entered the draught or current from the west. The sound was as loud as that produced by the effervescence of ale from a partially uncorked bottle, and similar in character, though a trifle more whistling in tone. It was accompanied by a strong smell, as of sulphuric or muriatic acid fumes. We all felt the prickling sensation in our fingers also, and a certain exhilaration. These passed away as we descended, and I should say left us entirely within 250 feet of the summit."

Similar experiences are described by M. Fournet, in the Comptes Rendus de l'Académie des Sciences of 1867, and also by M. Henri de Saussure, in an article translated for the Smithsonian Report of 1868. The cases enumerated are seven in number, and the circumstances strongly resemble those above related, except that the odor perceived by Mr. Dwight and his companions, possibly due to the presence of ozone, is not mentioned in any of them, though, in a number of these instances, the electric tension appears to have been very great, and, in almost all, there was a crackling of the soil and rocks themselves, and a peculiar vibration of the staffs or alpenstocks of the last observers, called the chant des bâtons. Invariably, according to the authorities quoted, there was an attendant shower of hail or sleet at the summit of the mountain. M. Fournet mentions also an instance of nocturnal luminosity on the Grands Mulets (Mont Blanc) as referable to a similar electrical condition.

De Saussure draws from the observations discussed by him the following conclusions:

1. The efflux of electricity from the culminant rocks of mountains is produced under a clouded sky, charged with low clouds, enveloping the summits, or passing at a small distance above them, but without the occurrence of electric discharges above the place whence the continuous efflux is proceeding. It would seem, therefore, that when this efflux takes place, it sufficiently relieves the electric tension to prevent lightning from being formed.

2. The continuous efflux of electricity from the ground toward the clouds is not unconnected with the formation of vapor, and probably also with that of the hail.

These electrical phenomena seem not to be rare in high regions, though they are by no means frequent. Many persons accustomed to climb mountains, such as guides and hunters, have never observed the electric resonance; others have heard it but once or twice in their lives. But, as De Saussure acutely remarks, it is precisely on those days when menacing skies repel adventurers from the highest altitudes that the phenomenon manifests itself.

If we now inquire what are the permanent physical traces left by this electric tension or efflux, we find nothing at all. Gray's Peak is a locality within my personal acquaintance, and it bears the marks of far other agencies than this. The whole mountain, for some hundreds of feet below the summit, appears to be a heap of broken fragments, sometimes erroneously called boulders. These have undoubtedly been produced from the exposed crags and ledges, and chiefly through the agency of frost. There is good reason to believe that this and many other summits have been frozen through, and that the summer thaws do not penetrate into their solid portions, except so far as disintegration may be still advancing year by year. I have been informed that the tunnel of the Baker mine, which is above timber-line on the Kelso Mountain, adjoining Gray's Peak, did not, by penetrating 200 feet, get beyond frozen ground. But neither the Baker mine nor the Stevens inine, which is about at an equal altitude on the McClellan Mountain opposite, nor any other of the numerous mines in our western districts, situated at great elevations, presents, so far as my observation goes, peculiar appearances referable to electricity as the cause.

In reply, then, to the assertion of electric theories of vein-formation, it may be said that they lack the basis of direct proof, and that the indirect evidence of analogy is against them. We are acquainted with certain effects of electricity upon rocks; these effects we do not find in ore-deposits; and what we do find there is referable to other causes. The prudent theorist will be content, for the present, with electrochemical, not electro-physical, action, and confine himself to the study, in this department, of the possible existence and effects of galvanic currents in vein-contents, depending upon chemical reactions.

APPENDIX.

THE BULLION PRODUCT.

Estimates of the bullion product of the country are as vague and variable as ever. In my last report 1 discussed at length the different methods by which it has been attempted to ascertain our production of gold and silver, and vindicated the estimates at which I had arrived by laborious and careful comparisons. I shall not here repeat the argument, but merely recall the fact that I showed the insufficiency of the data obtained by adding together the amount of domestic gold and silver deposited for coinage at the Mint and branches, and the reported amount of uncoined gold and silver bullion exported through the custom-house.

I shall give these figures for the year 1871 presently; but first I will quote a statement courteously furnished me by Mr. John J. Valentine, general superintendent at San Francisco, of Wells, Fargo & Co.'s Express. Mr. Valentine says:

With a view to ascertaining as accurately as possible the product of precious metals for 1871, in the States and Territories west of the Missouri River, I have caused statements to be carefully prepared at each of the company's offices showing the amount shipped monthly during the year named, viz, 1871. The results are:

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I submit the following as an approximately correct statement and estimate combined of the total yield of precious metals for the States and Territories of the United States west of the Missouri River, excepting New Mexico, for which I have no data,

viz:

Arizona shipments.

Estimate like amount forwarded by other routes and conveyances...

British Columbia shipments.

Estimate 20 per cent. by other conveyances

Colorado-excessive if any variation.

California.

Estimate 20 per cent. for undervaluation and by other conveyances..

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16,399,354 89

Idaho...

Estimate 20 per cent. by other conveyances

Montana...

Estimate 20 per cent. by other conveyances....

3,279,870 77

2,408,001 58

481,600 31

4,060,929 00

812,185 80

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I am confident that the allowance of 20 per cent. for, we may say, undervaluation and other conveyances, is a liberal concession, and that the total product did not exceed the above amount.

I take leave to differ widely in many points from these estimates, and for most of my corrections of them I have positive evidence. Mr. Valentine's addition of 20 per cent. for undervaluations and private shipments may be sufficient for California, but it seems far too little for Idaho and Montana, while for Colorado he makes no such allowance at all, but transfers the exact amount of the express shipments from his first to his second table, with the enigmatical comment, "excessive, if any variation." If this means anything, it means that the Colorado shipments of bullion are overvalued, and that the amounts upon which express charges are paid exceed the total amount produced! By comparing his figures with those given in my chapter on Colorado it will be seen that he ignores $923,000 shipped in matte, $500,000 shipped in ores, and $100,000 used by manufacturers, and that the product of the Territory is consequently about $1,523,000 more than he calculates.

With regard to Utah this statement is equally imperfect. He estimates the shipments of ores and base bullion at $1,000,000. This is a mere guess, and not a successful one. The shipments of ore from Salt Lake City in 1871 amounted to 10,806 tons, averaging at least $150 silver per ton, and the shipments of base bullion amounted to 2,378 tons, averaging $175 silver per ton. This gives us $1,620,900 as the value of the ores and $316,150 as the value of the base bullion, to which should be added $500,000 for the lead contained in ores and bars. The total of these items is $2,437,050, against $1,000,000 in Mr. Valentine's estimate. Considering that he makes apparently but $6,000 allowance for undervaluations and private shipments, it is quite within bounds to say that the product of Utah for 1871 was about $2,800,000, instead of $1,357,437, as he has it.

The express shipments from Arizona he doubles to obtain the total yield. I have direct evidence that this result is too small, and though I cannot say precisely how much too small it is, I believe my estimate is near the truth.

The British Columbia shipments are omitted from my table. The product of New Mexico, omitted by Mr. Valentine, was about $500,000, and the product of Wyoming, also omitted by him, was about $100,000.

In calculating for the whole country, east and west, I add, under the head of "other sources," $200,000 to cover the product of the southern States, and the extraction of silver from lead-ores not otherwise taken into the calculation.

My estimate of the gold and silver production of the United States for the year 1871 is as follows, compared with former years:

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I exclude from the statement for 1871 the product of the smeltingworks at Wyandotte, Michigan, which is believed to amount to $800,000, because the ores there reduced are obtained from Silver Islet, on the north coast of Lake Superior, and outside of the United States.

Further comment upon the above figures is unnecessary. It is evident that the product from placer-mining has continued to fall off, and that there has been a great advance in those districts which are chiefly ocсиpied with quartz mining. In California the placer and hydraulic mines have continued to suffer from lack of water; and the reduced product of that State is probably not to be taken as a measure of actual decline in these branches of mining.

The amount of gold and silver coined at the mints of the United States during the year ended December 31, 1871, is shown by the following tables furnished by the chief coiner:

Statement of deposits and coinage at the Mint of the United States, and branches, during the year ended December 31, 1871.

DEPOSITS.

Mint and branches.

United States Mint, Philadelphia

Branch mint, San Francisco

Branch mint, Carson City

Branch mint, Denver

Assay office, Charlotte

Total.....

Gold-deposits. Silver-deposits. Total deposits.

$2, 884, 645 61
24,960, 122 61
2,515, 132 79
1,020, 223 37
16, 122 37

31, 396, 246 75

$2, 124, 924 26
1,247,567 05
2,944, 465 17

2,937 67

164 52

$5,009,569 87 26, 207, 689 66 5,459,597 96 1,023, 161 04 16,286 89

6, 320, 058 67

37, 716, 305 42

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