LEAD.
Lead, the saturn of the ancients, is one of the most anciently known of the metals. It is found chiefly as sulphuret or galena, but a little in a metallic state also, as an oxide, and combined with several acids. It is a soft and flexible metal, of a pale livid grey colour, easily malleable, but slightly tenacious, and not sonorous. It is of common and extensive use in the arts. Alloyed with tin in different proportions, it forms solder and pewter, and with antimony it constitutes type metal. Combined with oxygen, it forms massicot, a protoxide of a pale-yellow colour. Litharge, also a semi - crystalline protoxide, obtained in separating silver from lead ores, enters largely into the composition of flint glass. Minium or red lead, deutoxide, extensively used as a paint, and also in the manufacture of flint glass. The carbonate of lead, or white lead, is a dense white powder, commonly employed as a pigment. The chromate of lead, of a beautiful yellow colour, is also much used as a pigment ; and the acetate, or sugar of lead, is employed for various purposes.
Galena is the richest ore of lead, and from which that metal is chiefly obtained. As met with in commerce, it is in heavy, shining, black or bluish lead-coloured cubical masses, having a great resemblance to the sulphuret of antimony.
The old lead mines of Kohel lie near the Red Sea, a day's journey N. by E. from Jabal Zubara, in about lat. 24° 40' N. Not far distant are the lead mines of Jabal Rassas, ht. mountain of lead. The mines are situated about 11 miles from the W. shore of the Red Sea, and the ores,—galena and carbonate of lead, occur in an argillo-siliceous schist, associated with small quantities of sulphur and iron,—a poor carbonate.
Lead ore is also found in Oman and at Ras-ul Had in Arabia, also in the mountains of Baluchis tan, where the nomade Brahui pick it up from the surface soil. Lead mines exist at Kappar in the hills contiguous to Baghwan and Kliozdar. Lead occurs at Rain, Chendak, Kerrage, I'atal, Dhunpore, and Jak. At Dessauly, about 55 cos east of Srinuggur, is a lead mine of considerable value.
Lead is worked at Jamu, and large quantities of galena are imported from Krtbul and Kandahar, under the name of Surma (antimony), from which natives of India do not distinguish it, and, being reserved for medicinal purposes, finds its way only to the druggists.
A mine near Sabiithu, in the Simla district, worked by a mining company, yielded 40 tons of ore monthly, and gave 16 to 72 per cent. of lead.
There is a lead mine at Baljawar, a day's journey north of the Oxus, so rich in the ore that the people who work at it for two months, earn sufficient for a year's subsistence.
In a defile close to Bamian there are 10 or 12 lead mines.
There are also lead mines at Lara, Leedang, Pokso, and some other places ; they are very pro ductive, but the lead is reckoned inferior to that of Sirmur and Jounsar. It sells at two or two and a half pounds per rupee.
In the Panjab lead is found in the districts of Kangra.
Lead and copper ores occur in the Ceded Districts ; galena lead ore at Coilguntla in the Dhone taluk, 30 miles S. of Kurnool ; also at Sidhout and Badwail, and near Jungumrazpilly, in the Nullatnallay Hills, 29 miles north-east of Cuddapah; the last-named substances occur in the sandstone formation.
In Dhone, galena in very large blocks was obtained ; one piece measured about 18 inches in diameter, and weighed upwards of 3 cwt. This ore was tried at the mint, and at the Madras School of Arts for glazing pottery ; it was found to succeed better when reduced to the form of minium, and then ground with felspar and an alkali. Examination of the Kurnool ore proved it to contain upwards of 1 per cent. of silver, or 374 ounces in the ton, the quantity of lead and silver together being only 45 per cent., which was occasioned by there being a considerable quantity of gangue disseminated through the portion examined. A further specimen of this unwashed ore was analyzed by Dr. Scott in 1859, and when fused with carbonate of soda and nitrate of potash, pro duced about 60 per cent. of metallic lead. The resulting lead, on being cupelled, furnished a bead of silver weighing 118 grs., which is equivalent to 96•64 oz. in the ton of ore, or 16516 oz. in the ton of metal. Malagah and Dorochet had found that when sulphide of silver is associated with the sulphides of other metals, it is always unequally distributed.