regarding the sulphur as combined with the iron and part of the manganese, the total percentage would be reduced by 2.25 per

cent.

Helvite has not previously been found in America.-H. Carvill Lewis.

A NEW MANGANESE MINERAL.-Mr. M. W. Iles has examined an efflorescence which occurs upon an ore vein in Park county, Colorado. The efflorescence is of a pure white color, is very soft, has a specific gravity of 2.16, and occurs in friable crystalline masses. It is soluble in water, and has a bitter, astringent taste. The aqueous solution has an acid reaction, indicating an admixture of free sulphuric acid. The following mean compo

The mineral appears to be a hydrous sulphate of manganese, containing perhaps admixtures of sulphatite, melanterite and goslarite. It should have further examination.

GALENA WITH OCTAHEDRAL CLEAVAGE.-About twenty years ago, Dr. John Torrey noticed at the Pequea mine, Lancaster county, Penna., a remarkable variety of galena, which had an eminent octahedral cleavage. The usual cubical cleavage was very indistinct, but was made more prominent after heating. He supposed the galena either to be pseudomorphous after fluorite or to be a dimorphous variety. Dr. Cooke, however, showed that by pressure, traces of an octahedral cleavage may be developed in galena from many localities, and Dr. Genth holds that such cleavage may be a natural result of octahedral crystallization.

A few months ago a similar variety of galena was found near Mont Blanc, Switzerland. A large crystal formed of two cubooctahedrons united by an octahedral face was found to give perfect and brilliant octahedral cleavage faces when struck by a hammer. The cleavage faces had a slightly undulating surface. The specific gravity of the crystal was 7.67. No alteration in cleavage was produced by heating.

THE CONDITION OF SULPHUR IN COAL.-Dr. W. Wallace1 has made some analyses of coal, which lead him to the conclusion that the sulphur found in coal, usually regarded as due to pyrite, exists frequently as an organic compound. He finds the amount of sulphur in many coals to be greatly in excess of the amount necessary to form bisulphide with the iron which is present.

At the recent meeting of the Amer. Inst. of Mining Engineers, Dr. Thos. M. Drown, probably not aware of these researches, contributed an interesting series of analyses of coals, which lead to 1 Proc. Phil. Soc. Glasgow, 1879-80, p. 223.

the same conclusion. He shows, moreover, that the "organic sulphur" in coal is not affected by the process of coking.

SPIRAL FIGURES IN CRYSTALS.-Students in optical mineralogy will be interested in an article by L. Wright, in a recent number of the Philosophical Magazine, entitled "Some Spiral Figures observable in Crystals, illustrating the relation of their Optic Axes." The author places a section of the mineral to be examined between a quarter-wave plate and a thick plate of quartz and examines this arrangement in a polariscope with converging rays. Beautiful spiral figures are produced, resembling the well known "Airy's spirals." A uniaxial crystal, as calcite, shows a system of double spirals, mutually enwrapping each other (Fig. 1.). A single axis of a biaxial crystal shows a simple spiral (Fig. 2), while if the section includes both axes of the biaxial crystal, as muscovite, two series of single spirals are observed, which, while separated from each other, finally enwrap one another (Fig. 3).

This a beautiful demonstration of the well known fact that the optic axis of a uniaxial crystal has a two-fold character. Fig. 1, representing a uniaxial crystal is seen to be composed of the same two spirals seen in Fig. 3, a biaxial crystal. A uniaxial crystal must therefore be regarded as a case in which the two axes of a biaxial crystal coincide.

Mineralogists will here perceive how slight a distinction exists between a uniaxial crystal and a biaxial crystal of small optic axial angle and will understand how, for example, a biotite having often no appreciable biaxial character may yet be regarded as monoclinic with an optic axial angle of nearly o°.

NATIVE SILVER.-Several interesting occurrences of native silver have recently been described.

The first of these is in the province of Almeria, Spain, where it has been found in iron ore. A bed of hematite of considerable

thickness forms a hill, at the base of which is a deposit of miocene marl containing occasional beds of argentiferous galena. The galena has long been worked for silver, and it is said that the Phoenicians and Romans once mined in that locality. Recently native silver has been found in the hematite itself, and in a bed of flint which overlies it. Veins of barite which traverse the hematite bed are also rich in native silver. The silver is said to occur in rounded grains.

Another interesting occurrence of silver has been described by Koenig and Stockder. They found it at a Colorado locality as clusters of crystals surrounded by or implanted in coal. The association of native silver with coal is a good demonstration of the accepted theory that organic substances play an important role in the reduction of metals from their salts.

According to a note in a recent number of the Engineering and Mining Journal, native silver has been discovered in small specks and scales at the copper mines near Somerville, N. J.

SOME VIRGINIA MINERALS.-The students in the laboratory of the University of Virginia, have contributed to the Chemical News several valuable notes upon Virginia minerals.

S. Porcher describes a native alloy of gold and silver occurring in rounded grains in Montgomery county. The grains have the color of gold on the exterior, but are almost white within. The specific gravity is 15.46, less than that of gold. Allowing for the partial removal of silver from the surface, the composition is shown to be represented by single atoms of gold and silver, AgAu.

T. P. Lippit has analyzed an epidote of clear pistachio green color, and finds that the iron is all in the ferric condition and that the mineral is about two-thirds aluminium epidote and one-third iron epidote.

B. È. Sloan has examined the beautiful bluish-white felspar which accompanies the microlite, columbite and beryl of Amelia county. This felspar resembles oligoclase, but is now shown to be a true orthoclase.

B. H. Heyward describes a zinc-bearing clay from Pulaski county; and A. L. Baker found that iodine was present in the salt brines of West Virginia.

NEW MINERALS.-Nocerine is a double fluoride of magnesium and calcium, which occurs in white acicular crystals in the volcanic rocks of Nocera.

Neocyanite is an anhydrous silicate of copper, which occurs in small deep blue crystals upon the lava of Vesuvius.

Tritochorite is a vanadate of lead and zinc, of a dark brown color and yellow streak, occurring in columnar cleavable masses.

Melanotekite is another massive, cleavable mineral of dark color. It is a silicate of lead and iron, occurring at Longban, Sweden. It has a metallic lustre, and is nearly as hard as quartz.

MINERALOGICAL NOTES.-A "crystalline bitumen" is found in trap at Port-a-Port bay, Newfoundland. It seems to have resulted from the heating action of the igneous dyke upon bituminous shales and limestones. These latter yield petroleum.— Artificial pseudomorphs of calcite after gypsum have been made by placing a crystal of gypsum in a cold, saturated solution of carbonate of ammonia. The change takes place gradually, and requires several days unless the gypsum is in fine powder, when a few hours suffice. The beautiful amianthus from Canada is found to be much finer than any asbestos for the manufacture of asbestos fabrics. It is said that the fabrics made from it are light, soft, and white. It is also felted into sheets, which are flexible, and unctuous to the touch. It is known in commerce as "Bostonite" or "Canadian fiber.”—An examination of a white slime which covered the bottom of a mine in Westphalia showed that it was composed of a mixture of Aluminite, Allophane and Hydrargyllite. A recent analysis of the water of the Dead sea showed it to have a spec. grav. of 1.186, and to contain the following number of grams of solid matter in one litre:

-Gold is reported as having been found in a ledge of quartzite near Amity, Orange county, New York. This is a locality already well known to mineralogists as having afforded many rare and beautiful species. In a specimen of Cerussite from Leadville, Col., analyzed by M. W. Iles, a small percentage of Massicot and a trace of chlorine was detected.

Mineralogists should beware of artificial moss-agates. They are being manufactured of great perfection at Oberstein, Germany. The coloring matter is introduced in chalcedony to form artificial dendrites.

GEOGRAPHY AND TRAVELS.1

EXPLORATIONS IN EQUATORIAL AFRICA.-Makua Land and the Interior of Mozambique.-Makua Land, the unexplored region. lying between Masasi and Mozambique and south of the Rovuma river has recently been traversed in different directions by three Englishmen. The Rev. Chauncy Maples, of the Universities Mission, advanced as far as Meto, about S. lat. 13°25′ E. long. 37° 58'. He was prevented by the cowardice of his native followers from continuing his journey to Mozambique. He heard reports of the existence of a snow-capped mountain called Irati, about 130 miles south-south-east of Meto and visible from that point in very clear weather.

Mr. H. E. O'Neill, British Consul at Mozambique, has recently undertaken the exploration of a route to Lake Nyassa which starts from Kisanga, opposite the island of Ibo. He found the country Edited by ELLIS H. YARNALL, Philadelphia.

for the first forty miles of his march from the coast at Mokambo Bay thinly timbered with thick undergrowth, including quantities of the India-rubber vine, fairly cultivated and populous. The country then becomes rocky and broken with hills and peaks of bold shapes and precipitous sides from 200 to 1000 feet in height. At the one hundred and forty-second mile of his march he speaks of coming into view of the exceedingly beautiful Shalawe plain, which, dotted with villages, stretches away for many miles to the west and south where the vista terminates in a range of splendid hills 2000 to 4000 feet high. Mr. O'Neill made a successful journey of 600 miles, returning at the end of November last, and we hope shortly to give some details of his explorations.

Mr. Joseph Thomson, who was sent by the Sultan of Zanzibar to examine some so-called coal beds on the Lujende river near its junction with the Rovuma, passed through the northern portion of this region and has sent an interesting account of his journey to the Royal Geographical Society. The "coal" turned out to be some irregular layers of bituminous shale of no practical use. Mr. Thomson's report so much displeased the Sultan that he at once broke the engagement he had made for a period of two years with Mr. Thomson, who has returned to England.

One of the members of the Universities Mission, the Rev. W. P. Johnson has also recently visited a lake; the source of the Lujende branch of the Rovuma. On reaching the banks of the lake he could see it stretching away to the south-east, the lofty hill Mangoche, near Nyassa, east of Mponda, being visible at the same time to the north-west. He supposes the lake to be the Lake Shirwa of Livingstone, the northern part of which has never before been visited.

Mr. Schuver's Expedition to Central Africa.-Petermann's Mittheilungen has received an account of the progress of Mr. J. M. Schuver on his journey from the Nile to Central Africa. He reached Fadassi on June 12, 1881. The source of the Termat affluent of the Blue Nile is in the Sori mountains west of Fasuder. Another stream of the same name near Belletafa is an affluent of the Jaboos river. He left Fadassi, on July 30th, on a trip of thirtyeight days to the south, during which he reached the country of the Légha Gallas near the source of the Jaboos. He also explored the Amam country which is watered by two affluents of the Jaboos. The watershed between the two Niles was defined as far as the eighth parallel. He saw far away to the south-west the great lake and river Baro flowing towards the west and situated a degree further south than as shown on Petermann's map. The Wallel mountain rises to the east to the height of 11,000 feet.

The Légha Gallas are a powerful tribe numbering 20,000 war riors, and inhabit a country far to the westward of the Galla country proper. Mr. Schuver proposed to leave Fadassi on January Ist, to explore the unknown regions down to the equator.