"The effects of driving sand extend to all parts of the desert where there are sand, rocks, or minerals to be acted on. On the upper plain north of the sand hills, where steady high winds prevail, and the surface is paved with variously coloured pebbles, these are all polished to such a degree that they glisten in the sun's rays. The polish is not like that of the lapidary, but more like that of lacquered ware, as if the pebbles had been oiled and varnished. On the lower parts of the desert, wherever silicified wood occurs, the sand has registered its action. When no obstacle has been encountered by the sand, the grains acting on each other have been almost perfect spheres."

Extent of the Gold Fields of California, &c.

According to Wm. P. Blake (see Silliman's Journal, xx., 72), the gold field of the Pacific slope extends from near the Tejon Pass, opposite the head of Tulare Valley, in lat. 35° continuously to the Umpqua River, in lat. 43° 45', and even beyond this, to the parallel of 49°, in the northern limit of the United States. Beyond the Umpqua there is little known, except that gold does occur at intervals; but south of it, the mining operations are at such frequent intervals as to show that this part of the gold field at least is nearly continuous.

The eastern boundary is not yet well defined, the higher parts of the Sierra Nevada not having been well explored.

The western range, along the Sacramento and San Joaquim, is better known, but it is irregular.

The greatest breadth of the field is from the Shasta to the coast at Gold Bluffs, south of Klamath River, lat. 41° 30', where it is 110 miles wide.

From the Yerba River southward, the breadth is about 50 miles, and this is about the average expansion of the whole field. It contracts going southward, and near the end of the Sierra Nevada it is only about 10 miles broad, where it finally terminates.

From the Umpqua River, on the north, to its southern end, it includes 9° of latitude, or a length of 700 miles; this, with the average breadth of 50 miles, gives an area of 35,000 square miles.

Taking the extreme northern limit, the length of the gold field covers 14° of latitude, or nearly 1000 miles.

Gold is found in the sand of the coast, at various points between Gold Bluffs, 30 miles south of Crescent city to the Umpqua River. The most important localities are near Port Orford, between Gold River and Coose Bay, distant 80 miles from each other.

The gold dust occurs in the beach sand from the surface to a depth of more than six feet. This sand is a black sand, containing very thin small scales of gold, mixed with platinum and other metals, which are separated with difficulty. This black sand is in enormous quantities-is irregularly stratified or sorted by the tides. The storms stir these sands to a considerable depth, renewing the gold on the beach after it has been exhausted by superficial mining.

Other detached gold placers occur south of the Sierra Nevada, in the south side of the San Bernardino chain, near San Fernando and San Francesquito, in talcose slates.

Gold exists in the Great Basin, 170 miles from Los Angelos, in place; it is in filaments, in quartz.

Gold has also been found in Colorado Desert, near the Fort Yuma, at the mouth of the Gila.

Dr Trask, in his report on the Geology of California (1855), classifies the gold mining districts of California into three ranges or belts, denominated the Upper or Eastern Range-the Middle Placers-and the Valley mines.

Eastern Range.-Extends from near summit of mountains to within about 25 miles of edge of plains.

Maintains uniform breadth of about 20 miles, and has a known length of 130 miles.

Covers an area of about 3000 square miles—a large proportion of this being available for mining.

The greater part of the so-called dry diggings occurs in this belt. Considers the productive Placer deposits as at least one-third of this area, or equivalent to a mining ground of 1000 square miles.

Of this large area, only a surface of about 20 square miles, or two per cent., is yet opened, or in any manner improved."

66

The amount of ground in 14 mining counties now under improvement does not exceed 300 sq. miles. This is the region of the deep diggings. Middle Placers.-These occupy a range of country bordered on the east by a line 20 miles from the higher foot hills, and on the west by a line of about 4 miles up from the eastern edge of the plains.

This belt also is about 20 miles broad, but its length is 300 miles, and its area 6000 square miles.

In this belt occur the surface workings, though in some deposits the gold lies nearly as deep as in the higher mountain belt.

The ordinary depth of the Placer, or gold-bearing drift, in this district, is between 12 and 40 feet. This stratum is more heterogeneous in composition than the drift of the higher range.

The floor of the auriferous drift, or "bed-rock," consists in this district mostly of highly-inclined slates, occasionally of granite.

This middle range contains at present the chief mining operations of California.

Valley Mines.-The third, or western belt, extends in breadth from the lower foot hills of the mountains westward into the eastern edge of the plains of the San Joaquim and Sacramento, a distance of from 3 to 5 miles, ranging in length from Chico Creek, in Butte Co., to the Mercea River a distance of 250 miles.

The gold-bearing gravel of this zone is very ferruginous; the richer deposits vary in depth from 3 to 8 feet, and rest on sandstone and slate, or on clay beds, above these rocks; though the shallowest, these deposits are the most easily worked.

The western limit of the auriferous drift is generally well-defined. It is marked by a sudden change from the soil of the plains to a surface thickly strewed with small angular pebbles of quartz, covering a belt from 2 to 4 miles wide.

On the eastern verge of the plains there is an equally sudden transition from angular pebbles to rounded pebbles, mixed with alluvium, succeeded by outcrops of the slates.

Water. The natural supply of water, indispensable to gold mining, is restricted to about four months in the year in California.

Water is now carried to great distances by canals from the mountain ravines and valleys, where streams exist, to gold-bearing deposits not naturally supplied with it.

There are about twenty-three canals dispensing water to the mines on the surface of the valley, and there are 109 companies engaged in seven of the principal mining counties in conveying water for mining purposes. Indeed, some very colossal enterprises are on foot for an erection of canals and aqueducts for the irrigation of the mines, especially on the upper diggings.

Methods of mining.-In the deeper deposits, the mining does not consist, as in the shallower, of open digging, but is genuine subterranean mining. Some of the adits are 100) and 1200 feet long, and few shorter

than 300 feet, and large enough for a horse to carry the auriferous earth to the sluice outside where it is washed. Some of the adits are driven through solid rock.

In certain districts, instead of underground workings reached by an adit, a broad ditch is carried round the slope of the hill, and the whole earth of the hillside removed and washed, tossed from one level to another.

The scale of these mining operations can be inferred from the statement, that some of them have cost 40,000 dollars, or L.8000 preparatory outlay.

The opening of the Mameluke Hill, requiring this expenditure, repaid in a period of little more than a year L.100,000; other localities have been still more productive.

Miners employed. The extent of ground actually occupied for mining seems not to exceed 400 square miles. In the year 1852, 100,000 men were engaged, it was estimated, in extracting gold within that area, and their product was 45,000,000 dollars; the actual number since engaged has not exceeded 86,000; in 1854, 80,000, while the product of this latter year was 61,000,000 dollars, or 750 dollars per man.

Trask estimates the aggregate areas of the gold-containing deposits of California at 11,000 square miles.

General Statistics of Gold.

In 1848, the total amount of gold in use in the world, was estimated by the best authorities at about £600,000,000 sterling, and the annual supply was believed to be between eight millions and nine millions sterling. From the recent extraordinary influx consequent on the opening of the gold fields of California and Australia, we may compute the amount now in hand at about £820,000,000 sterling. The data in this estimate are as follow:

From a table in Westgarth's Victoria, it appears that these two regions have produced as follows:

All other sources in the five years

£659,000,000 35,000,000 40,000,000

To those add the present product of £50,000,000 per annum from

all quarters for two years

100,000,000

£834,000,000

From this deduct for waste, estimated at £2,000,000 per annum for seven years

14,000,000

£820,000,000

This net product now in the world is equivalent to about 205,000,000 ounces troy, or 8542 tons. Great as the amount seems, it could be all contained in a cubic block of gold only 23 feet in diameter.

The gold coinage in Great Britain, France, and the United States, amounted in 1843 to £4,200,000, and in 1853, it was £41,800,000, or nearly tenfold as large.

H. D. R.

Remarkable Formation-California.

The geological formation of that portion of Spanish Hill which has contributed most to its celebrity, as one of the richest gold deposits ever found in California, is one of the most singular and interesting we have ever seen. It consists of a very deep basin, the rim rock protruding out of the ground on nearly every side, so that although one may stand on the bed rock at the top of the hill, not six feet distant a shaft might be and has been sunk over one hundred feet. In the bottom of this basin are three crevices, the middle one of which, running longitudinally, through the Golden Gate claim, is most singularly formed, presenting the appearance of a quartz lead, of uniform width-about fifteen feet and dipping towards the east. But, instead of being filled with quartz rock, it is filled with gravel, and massive, round, hard and smooth quartz boulders. The earth taken from this crevice, from the top of the ledge as far down as the shaft was sunk (about ninety feet), paid on an average a little over sixty ounces to every four hundred barrowsful, and the crevice at the east side of, and running parallel to this, being partly on the Golden Gate and partly on the Hook and Ladder claim, paid on an average a trifle over one hundred ounces to the same quantity of earth. The highest taken out of one day's washing, was one hundred ounces. But the most curious piece of work ever done in this, or perhaps in any other country, is now in preparation in the Hook and Ladder claim. The proprietors have been engaged for about four months, day and night, in cutting a tunnel through the bed rock, from a very low point, so as to strike the bottom of the basin. By a recent survey, they have ascertained that they have but a few more feet to run. As soon as they break through the rock and reach dirt, the skilful and enterprising proprietors intend to bring the water immediately over the mouth of their tunnel at a perpendicular height of two hundred feet, where it will be received by a strong hose running up through the tunnel-in which their sluices, and a car to carry off the rock, will be placed. It is intended to literally tear out the very bowels of the hill, so that nothing but a shell will remain, and, doubtless, some day the hill will fall in with a tremendous crash. Spanish Hill is supplied with water by the South Fork canal.

Reptilian Remains found in the Old Red Sandstone of Morayshire. About fourteen years ago, Mr Patrick Duff discovered in the red sandstone of Lossiemouth, near Elgin, a slab with peculiar markings, which, on being submitted to M. Agassiz, were pronounced by that celebrated palæontologist to be the impressions of the scales of a fish which he named Stagonolepis. Last May, in a quarry to the east of Quarrywood, a little north of the town of Elgin, another slab was discovered bearing exactly similar impressions to the former one, but associated with these markings were several large bones and some distinct vertebra, which exhibit the reptilian characters. This last fossil becomes highly interesting as connected with the discovery, some years ago, in an adjacent quarry of Spynie, of the complete skeleton of a smaller reptile. There are in this district three beds of the Devonian sandstone. 1. The lowest bed containing the Pterichthys and other fishes. 2. The middle or gray, characterized by the remains of the Holoptychius. 3. The upper yellow beds, containing the reptilian remains. Above these is a bed of unfossiliferous limestone or cornstone that separates the Devonian strata from the more superficial Oolitic formations which are partially scattered over part of the district. These three beds of the Devonian formation are placed conformably on each other, and the cornstone can be traced superimposed over a considerable portion of the district, so that there is a distinct separation between the older Devonian and the newer superficial outliers of the Oolitic. We hope to be able to give a more particular account of the reptile bones in a subsequent number.

CHEMISTRY.

On the Equivalent of Antimony. By R. SCHNEIDER.

The equivalent of antimony is taken from Berzelius' experiments at 129 (H=1), but, according to Schneider, it ought to be reduced to 120-25. This number is arrived at by the analysis of a native sulphuret of antimony of remarkable purity. The reduction of this sulphuret by means of a current of hydrogen was employed as the basis of the determination of the atomic weight. The author found that this reduction could be effected almost completely at a temperature at which scarcely an appreciable trace of the sulphuret is volatilized, provided the current of hydrogen be not too rapid. Taking into account a small quantity of sulphuret which sublimes (from 0.0005 to 000125 grammes) and of sulphur which adheres with obstinacy to the antimony, from (0·001 to 0·007 gr.) where from 3 to 10 grammes were employed for the experiment, he obtained in six experiments

giving 120-25 for the equivalent of antimony. The author promises the details of his experiments in a future paper.-(Poggendorfs Annalen, vol. xcvii., p. 483.)

On Silicon. By F. WÖHLER.

In experimenting on the preparation of aluminium by Rose's method from cryolite, Wöhler employed Hessian instead of iron crucibles, and found that he frequently obtained in addition to the malleable buttons of aluminium, brittle globules, containing a crystalline substance. By digesting them with hydrochloric acid, the aluminium dissolved, leaving dark iron black crystalline scales, having a metallic lustre, and which proved to be silicon in the crystalline form recently discovered by Deville. In considering the mode in which the silicon was here produced, it was obvious that silico-fluoride of sodium had been formed by acting on the mass of the crucible, and that it had been reduced by the aluminium. Acting upon this view Wöhler has found it possible to obtain at will the silicon in this state. For this purpose aluminium is fused for about a quarter of an hour with 20 or 30 times its weight of silico-fluoride of sodium. On breaking the crucible a well-used dark iron-gray regulus is obtained, which consists of a compound of aluminium with silicon, containing a large quantity of the latter substance in a crystalline form. The mass is broken, digested first with hydrochloric acid, and then with moderately strong hydrofluoric acid. In this way there are obtained for every 100 parts of aluminium 70 or 80 of a regulus, containing from 65 to 75 per cent. of crystallized silicon. It is in the form of shining scales resembling natural graphite, but with a more metallic lustre. By the use of a large quantity of aluminium, crystals of considerable size may easily be obtained. It is harder than glass-sp. gr. 2.490. It does not burn in the air, and even when heated in the spirit lamp flame, alimented with a current of oxygen, does not lose its metallic lustre. At a low red heat it burns in chlorine. It is insoluble in all acids, but dissolves in solutions of the alkalies.-(Poggendorff's Annalen, vol. xcvii., p. 484.)

On the Detection of Strychnine.

"Edinburgh College, June 1856.

"MY DEAR SIR,-The detection of strychnine has of late so much engaged public attention, that perhaps some of the readers of your Journal