by that mineral, although of two pieces of wood lying in close proximity to each other, one may have become silicified, whilst the other is replaced by iron pyrites.

The assay of several specimens of the cementing pyrites showed that it invariably contained a certain but very variable amount of gold. In order to ascertain whether this exists in the form of water-worn grains mechanically enclosed within the sulphid, or in the form of spongy, crystalline, and filamentary particles, similar to those met with in the pyrites of auriferous veins, various samples were dissolved in nitric acid, and the the residues afterward subjected to microscopical examination. In this way granules of the precious metal, which had evidently been worn by the action of water, were detected, whilst others appeared not to have been subjected to such attrition. Mr. Ulrich states that in the golddrifts of Australia, pyrites is often found replacing roots and driftwood, and that samples have, on assay, yielded from a few pennyweights to several ounces of gold per ton.

Hot Springs.-Hot and boiling springs are exceedingly numerous throughout California; and considerable accumulations of sulphur, together with evidences of extensive solfatara action, are met with in different sections of the State.

The most remarkable instance on the Pacific coast of the actual growth, on a large scale, and at the present time, of mineral veins, is probably that afforded by the boiling springs in Steamboat Valley, about seven miles northwest of the great Comstock silver vein in the State of Nevada.

These springs are situated at a height of about 5000 feet above the level of the sea, at the foot of the eastern declivity of the Sierra Nevada. The rock in this locality presents several straight and parallel fissures, either giving out heated water or simply ejecting steam. The first group of crevices comprises five longitudinal springs extending in a straight line, and parallel to each other, for a distance of above 3000 feet. These fissures are partially filled by a siliceous incrustation, which is being constantly deposited on the sides, whilst a longitudinal central crevice allows of the escape of boiling water or steam. On the most eastern of these lines of fracture are five active centers of eruption, from which boiling water is sometimes ejected by the force of steam to a height of from eight to ten feet. These waters are alkaline, and contain, in addition to carbonate of soda, the sulphate of that base, together with chlorid of sodium. There is also everywhere an escape of carbonic acid, whilst from some places sulphuretted hydrogen is also evolved. These products, on arriving at the surface, give rise to the deposition of sulphur, silica, and anhydrous oxyd of iron. The silica and oxyd of iron form semi-crystalline bands parallel with the walls of the fissures; and spongy deposits accumulate around some of the points of most active emergence.

At a considerable distance to the west of those above described, a fissure having the same origin is observed; but this is no longer

traversed by currents of hot water, although it still gives off steam and carbonic acid at various points throughout its extent. At its northern extremity a central fissure still remains open; but in other localities it is, for the most part, obstructed by siliceous concretions. This siliceous rock is metalliferous, and, in addition to oxyd of iron and manganese, contains iron and copper pyrites. M. Laur states that he also discovered metallic gold in this deposit.

The rock enclosing the veins of Steamboat springs is granite, which in their vicinity is much decomposed, being often reduced to a cavernous skeleton of silica containing a few scales of mica.

Alkaline Lakes. In that portion of California lying on the east of the Sierra Nevada are Mono Lake and Owen's Lake, both considerable sheets of water, highly impregnated with alkaline salts. Owen's Lake lies in lat. 36 20" south, long. 118° west from Greenwich, and is about twenty miles in length and eight in width.

The waters of this lake have a specific gravity of 1.076, and contain 7128-24 grs. of solid matter per gallon. The salts held in solution are chiefly carbonate and sulphate of soda, with chlorid of sodium; but potash, silica, and phosphoric acid are also pres

ent.

The incrustations, which at certain seasons of the year are found to the extent of many hundreds of tons, consist of a white spongy efflorescence, and are, as will be seen from the results of the analysis given in the paper, chiefly composed of carbonate of soda, mixed with a little chlorid of sodium and sulphate of soda.

General deductions.-The author remarks that, in the present state of our knowledge, the results of a careful examination of the gold-regions of the Pacific coast would appear to lead to the following conclusions:

a. Quartz veins have generally been produced by the slow deposition from aqueous solutions of silica on the surfaces of the enclosing fissures.

b. From the general parallelism with its walls of the planes of any fragments of the enclosing rock which may have become imbedded in a vein, it is to be inferred that they were mechanically removed by the growth of the several layers to which they adhered, and that a subsequent deposition of quartz took place between them and the rock from which they had become detached. In this way were introduced the masses of rock known as "horses

c. The formation of quartz veins is due to hydrothermal agencies, of which evidences are still to be found in the hot springs and recent metalliferous veins met with in various parts of the Pacific coast.

d. From the variable temperatures at which the vacuities in their fluid-cavities become filled, it may be inferred that they are the result of an intermittent action, and that the fissures were sometimes traversed by currents of hot water, whilst at others they gave off aqueous vapor or gaseous exhalations. This is pre

cisely what is now taking place at Steamboat springs, where the formation of a vein is in progress, and from which currents of boiling water are often poured forth, whilst at other times the fissures give off currents of steam and heated gases only.

e. That gold may be deposited from the same solutions which give rise to the formation of the enclosing quartz, appears evident from the presence of that metal in pyrites enclosed in siliceous incrustations, as well as from the fact of large quantities of gold having been found in the interior of the stems of trees, which in deep diggings are often converted into pyrites.

f. The constant presence of iron pyrites in auriferous veins, and when so occuring its invariably containing a certain amount of gold, suggests the probability of this sulphid being in some way necessarily connected with the solvent by which the precious metal was held in solution. It has been shown that finely divided gold is soluble in the sesquichlorid of iron and, more sparingly, in the sesquisulphate of that metal. It is also well known that iron pyrites sometimes results from the action of reducing agents on the sulphates of that metal. If therefore sulphate of iron, in a solution containing gold, should become transformed by the action of a reducing agent into pyrites, the gold at the same time being reduced to the metallic state, would probably be found enclosed in the resulting crystals of that mineral.

g. The silica and other substances forming the cementing material of the ancient auriferous river-beds have probably been slowly deposited at a low temperature.

The connection existing between the decomposition of granite by the agency of boiling springs, the existence of alkaline plains, and the formation of lakes containing various salts of soda and potash, is too obvious to require comment.

4. Gold in Rhinebeck, Dutchess county, New York.-Reports on the auriferous quartz veins of Rhinebeck, have recently been published by Prof. J. G. Pohlé and Prof. John Torrey. According to the former, there are four veins dividing the talco-argillaceous schist in the direction of the cleavage. The quartz is cellular, and brown, with oxyd of iron arising from the decomposition of pyrites; but below it is more compact, and the pyrites is unaltered. Analysis of the rock afforded Prof. Pohlé 963 to 975 thousandths of gold, the rest almost solely silver. Prof. Pohlé adds: "The geological formations on this property are of the Lower Paleozoic age; the Potsdam periods of it are well represented by the metamorphic slates and the calciferous sandstone, but no fossils have thus far been found. The slates (argillaceous mainly) form a characteristic feature of the whole Appalachian range, and the presence of gold here, supplies the link heretofore wanting, in the chain. of the Appalachian gold fields; for there can be no doubt that this is a part of the grand belt, taking its rise on the St. Lawrence river and scattering its auriferous treasure for thirteen hundred miles, along the southeastern border of North America, terminating in Alabama.

The discovery of gold in this part of the Appalachian_gold fields is due to the scientific attainments and perseverance of E. G. Freligh, M.D."

Dr. Torrey assayed a quantity of the quartz procured by him at the mine, it being "a fair average of the lode," and amounting to several hundred pounds, and states as his results, that of three assays the average yield of gold per ton of ore (2000 lbs.) was $118.49. In no case was the proportion of gold less than $100 per ton.

III. BOTANY.

1. Botanical Necrology for 1868.-The most distinguished name upon the list is that of

GEORGE A. WALKER-ARNOTT, Professor of Botany in the University at Glasgow, who died on the 17th of June last, in the 70th year of his age. He was born in Edinburgh, Feb. 6, 1799, educated at the celebrated High School of that city, and at the University, where he took high rank as a scholar, especially in the mathematics, publishing two papers in Tilloch's Philosophical Magazine in 1817 and 1818, while yet a student in arts-and then, turning to law studies, he was called to the bar, as a member of the Faculty of Advocates in the year 1821. He hardly entered, however, upon the duties of his profession, his taste for natural history having been early developed under the lectures of Prof. Jameson and of Mr. Stewart,-the latter a well-known teacher of botany at that time, and his patrimonial estate of Arlary in Kinross-shire sufficing for his support, so that he could devote himself to botany, as he did, with unsurpassed ardor and success. His earli est botanical paper, upon some Brazilian Mosses, was written in French and published in a journal at Paris, in 1823. In 1826 and 1827 he contributed to the Edinburgh New Philosophical Journal a lively narrative of a botanical tour to the South of France and the Pyrenees. He resided for some time at Montpellier, and in Paris, examining the principal herbaria there, also that of DeCandolle at Geneva, and in 1828 the herbaria at St. Petersburgh. In 1831 he married and established himself with his collections at Arlary, where he resided until in 1845, he accepted the professorship of Botany in the University of Glasgow. It was during these fourteen years that the vast amount of scientific work he was able to accomplish was mainly done. He wrote the article Botany in the seventh edition of the Encyclopedia Brittanica,-the best treatise of the kind of its day in the English language, and one of the most influential. In conjunction with his early friend, Sir Wm. Hooker, he wrote the Contributions to the Flora of South America, &c., which form a long series of articles in the Botanical Miscellany, Journal of Botany and other similar periodical or serial publications edited by Sir William. He took a similar part in the Botany of Beechey's Voyage; in connection with Dr. Wight he brought out the first volume of the Prodromus Flora Peninsulæ Indiæ Orientalis; and made numerous contributions to various periodicals.

Up to 1845 or somewhat later Dr. Arnott was one of the foremost botanists of the time, one of the most zealous and sagacious, versed alike in European and exotic botany. But upon assuming the duties of his chair at Glasgow he appears soon to have abandoned the field in which he had won the highest honors, and in which much more was justly expected. He assumed, however, the joint authorship of Hooker's British Flora, taking, we believe, the whole charge and responsibility of the later editions. As he began with Mosses, so for the last fifteen or twenty years of his life, he devoted himself principally to the Diatomacea, bringing to their investigation all the ardor of his nature and the keenest powers of observation combined with indomitable patience and unwearied care. So that he became in this department of microscopical research one of the highest authorities, and amassed one of the richest collections extant. As a professor he was greatly esteemed and respected, although he may be thought to have come almost too late in life to the professor's chair. In his later years he was much withdrawn from general botanical intercourse; but his surviving correspondents and friends on this side of the ocean cherish very pleasant memories of him.

NATHANIEL BAGSHAW WARD, Fellow of the Royal and Linnæan Societies, after whom, as its inventor, the Wardian case is named, died, at the ripe age of 77 years, on the 4th of June last. He was born in the east end of London, where his father was a medical practitioner of repute, and where for the greater part of his busy and most useful life he laboriously devoted himself to the same profession. About twenty years ago he exchanged the smoke-charged atmosphere and dingy dwellings of Wellclose Square for the pleasant and airy suburb of Clapham Rise, but still actively engaged almost to the last in professional practice and in his various official duties, mainly in connection with the Apothecaries' Society, filling in succession nearly all its important offices. The renovation and even the maintenance of the celebrated Apothecaries' Garden at Chelsea-the oldest botanical establishment of the country-is probably mainly due to his counsels and exertions. We cannot here enter into the interesting history of the invention of the now familiar Wardian case,-a discovery which grew out of Mr. Ward's persistent endeavors to cultivate the plants he delighted in under the smoke and soot of the dingiest part of London, and which resulted in providing for the poor as well as the rich denizens of the smoky towns of the Old World the inexpensive but invaluable luxury or comfort of being surrounded at all seasons with growing plants and fresh flowers. Nor is the invention less applicable to house-culture, especially of Ferns, under the clearer and purer air of our own country rendered arid by the cold of winter, as hundreds could testify who have enjoyed the benefit, perhaps without knowing even the name of their benefactor. Equally important is the application of the Wardian case to the conveyance of living plants between distant countries. The writer well remembers the first case of growing