The distribution of graphite in Asia is by no means inconsiderable. A deposit, said to be very abundant, has been discovered in the Bagoutal mountains of S. Siberia, near the Chinese frontier, of which great things are predicted. Seebohm, in 1879, brought about 20 tons of almost pure graphite from the banks of the Kiireijka. The deposit is leased by a Russian from his government, and has not yet been the scene of anything like scientific working. Two samples of Siberian graphite from Stephanovsky respectively revealed on analysis the following composition :—Carbon, 36.06 ; silica, ; ferric oxide, 4.02,3.05 ; alumina, 17'80,15.42 ; lime and magnesia, ; volatile matters, 3.20, 4.03 ; sulphur, traces, English graphite is said to he imported into Russia, for admixture with the low-grade native produce. Deposits of lamellar graphite have been found in several parts of India. In 1862, a new mine was discovered at Sonah, near Goorgaon. The mineral is found in masses of variable size, and generally quite detached. In some cases, the surrounding rock is impregnated with graphite, mixed with small micaceous particles. It yields on analysis :—Carbon, ; silica and alumina, 12.98 ; peroxide iron, ; carbonate lime, ; water, ; alkaline sulphates and chlorides, 0.08. The soil and rocks of Ceylon are almost everywhere impregnated with graphite, so that it may even be seen covering the surface in the drains after a recent shower. That found at Ratnapoora and at Belligam is in large detached kidney-shaped masses, at 4 to 24 ft. below the surface. The cost of digging and transport are the chief expenses attending it ; the supply is practically inexhaustible. The mineral exists in such quantities in the gneiss rocks that, upon their decomposition, it is seen in bright silver-like specks throughout. Graphite-diggings are scattered throughout every part of the island, and are numbered by hundreds, and fresh discoveries are constantly being made. Ceylon graphite is particularly remarkable for its purity, containing as it does very small proportions of siliceous ash. Three samples revealed the following features :— 1. Amorphous, sp. gr., 2.2671 ; volatile matters, carbon, 99'792%; ash, % 2. „ 2.2546 ; 0'000 ; 7, 3. Foliated „ ; 7? 0.108 „; „ 99'679 „; „ 0.213 Graphite mining on private lands was subjected to a Royalty by the local government as early as 1851. The amount was then fixed at 4s. per tun of mineral raised, which was increased to 5s. in 1852, 7s. Cal. in 1859, 14s. iu 1862, 16s. in 1864, and 30s. in 1869. In consequence of the difficulty experienced in collecting this Royalty, it was abolished in 1873, and was replaced by an export duty of 11. per ton, levied by the Custom House on all graphite exported beyond the seas. This came into force on the let April, 1874. The quantity and value of graphite exported from Ceylon for seven years ending 1877 have been as follow :-1871, 125,257 cwt. (62,0951.); 1872, 136,051 cwt. (13,8370; 1873, 173,996 cwt. (147,9391.); 1874, 149,938 cwt. (135,0161.); 1875, 110,023 cwt. (103,1160; 1876, 117,361 cwt. (110,0260 ; 1877, 96,792 cwt. (90,7431.). The mineral has also been recognized in Burma!), and has been contributed in small quantities from Vizagapatam and Malacca. The general Indian product is net sufficiently fine for pencils, but is available for crucibles.
Little as we know of the African continent, graphite has already been found in many parts of it. A very good quality is found to the south of Springvale, in Natal, in gneiss. As the working is not very expensive, a ton of pure mineral costing only about 301., hopes are entertained that it will pay to ship. Traces of graphite are met with at several points in the " old colony." A con siderable deposit occurs not far from the mission station of Inyatin, about 20° S. lat. In 13ambs. Hill, Southern Usambara, Keith Johnston found it disseminated through the mass of the rock, a garnetiferous gneiss.
Graphitiferous rocks of the Laurentian system are widely spread throughout Canada and some parts of the United States. The graphite of these rooks usually occurs in beds and seams, varying in thickness from a few inches to 2-3 ft. They are often interrupted, giving rise to lenticular masses, which sometimes are nearly pure. The deposits generally occur in the limestones, or in their immediate vicinity, and granular varieties of this rook often contain largo crystalline plates of graphite. At other times, the mineral is so finely disseminated through the limestone as to give it a bluish-gray colour, and the distribution of the stained bands servea to mark the stratification of the rook. The graphite of the Laurentian series is not, however, confined to the limestone.
Perhaps the most important and extensive of the Canadian deposits is that near the township of Buckingham. Here the graphite occurs both in beds or veins, and disseminated. The veins are fourteen in number, some 6-10 ft. wide, and 3-14 in. thick, besides more or leas disconnected lenti cular masses, yielding 30-35 per cent. of mineral. The vein graphite is of two varieties : (a) foliated : of dense, massive structure ; made up of broad and thick laminae; colour, dark steel-grey ; lustre, metallic ; ap. gr., carbon, ash, volatile matters, 0.178 per cent. ; (b) columnar : carbon, ash, volatile matters, 0' 594 per cent. ; sp. gr., 2'2679. Second samples of each gave ; (a) sp. gr., ; volatile matters, 0.109, carbon, 99.815, ash, 0.076 per cent. ; (6) ap. gr., 2.2659, volatile matters, 0.108, carbon, 99.757, ash, 0.135 per cent. Besides this vein graphite, there is a quarry of the disseminated mineral, more than a mile long, and 70 ft. high, giving 10-60 per cent., the average being about 25 per cent.
The graphite is here prepared or " dressed" for the market in the following way :—The crude ore is stamped fine in water, and then put through buddies, by which the graphite and the rock matter associated with it are separated according to their specific gravities. The graphite is sub sequently charged into reverberatory furnaces, and ultimately passed through bolters, whose gauze is of various degrees of fineness, according to the size required. According to Hofmann, the Canadian graphites equal those from Ceylon in point of incombustibility, and on that score are as well fitted for crucible making. On the other hand, all the samples examined contained more or less carbonate of lime and oxide of iron, both exceedingly objectionable in graphite intended for refractory purposes. By a process of treatment to be discussed further on, it is possible, however, to remove these and other foreign matters, so that " dressed " mineral showing 13-15 per cent. of impurities, may contain only 6.69 per cent. after treatment 5.33 of this amount being silica. In this way, the Canadian graphite can be rendered quite fit for crucibles, &c. Its cost price after dressing is about 31.-51. per ton. Workable deposits of graphite also occur in the Dominion, near the townships of Burgess, Lochaber, and Grenville.
There are two important graphite miuce in the United States, the principal being the Eureka mine, near Sonora, California. The lode from which the mineral is obtaiued runs about 4000 ft. in a N.-E. and S.-W. direction, and ranges from 29 to 40 ft. in width. It is much broken up and mixed with the surrounding rock and earth to a depth of about 30 ft., but below this it is well defined between walls of sandstone and clay-slate. The lode is frequently divided by lenticular masses of clay-slate, from a few inches to several feet in thickness. A shaft sunk on the lode to a depth of 65 ft. showed the mineral to be purer and more solid than at the surface. The lode continues 25 ft. wide, and much of the mineral is so pure that a couple of men can extract and sack about two tons daily of a quality that can be sent to market without any preparation.