CLASS I-MINING, QUARRYING, METALLURGICAL
OPERATIONS, AND MINERAL PRODUCTS.

SITUATION OF CLASS.-Near the Southern Wall of the
Building, occupying the space between the Western End and
the Exit Door adjoining the British Sculpture Room. Between
Pillars R. and S. from 1 to 27.

Position of Groups (Numbers referring to Pillars).—Crystals, Gems, Ornamental Stones; Models of Crystals, and Educational Collections; Fossils, &c., 1 and 2.-Salt; Mineral Manures; Soils, Sand, Plumbago, to 4.-Potters* Clays and Cements, to 6.-Granites, Marbles, Slates, to 9.-Coal, Coke, Peat, to 14.-Iron Ores, Manufactured Iron, Models, &c., to 18.-Models of Coal Mines, Copper Ore, Dressing Machine, Zinced Iron, Zinc, Tin Smelting, to 21.-Copper, Tin, and Iron Ores; Models, Tools, &c., to 24.-Platinum, Cobalt, Gold, Silver, Lead; Metallurgical Processes, &c., to 26.

Gems and Ornamental Stones (Exhibitors 2, 3, 4, 10, 11, 15, 16, 19, 20, 22, 24, 25, 28, 31) and the Koh-i-Noor. -The crystals of diamond here exhibited are instructive as showing the way in which diamonds are found mixed with silicious pebbles, grains of gold, oxide of iron, &c. The specimen exhibited is from the Duke of Buckingham's collection, and is figured in Mawe's "Treatise on Diamonds and Precious Stones." The models of the largest diamonds known are associated with this. In connection with the more brilliant collections found in other parts of the exhibition, any historical notices will be more appropriately appended. A few remarks may, however, be introduced on the mode of occurrence and the physical constitution of this beautiful gem. Brazil supplies Europe with the largest number of diamonds, the oriental diamond beds appear

ing to be nearly exhausted. The diamonds of India were principally found in the kingdoms of Golconda and Viziapour: those of Brazil, discovered in the seventeenth century, and at first used as card-counters, are found in the district of Serro-do-Frio, in a conglomerate called cascalho, from which they are extracted by washing. Diamonds are always found crystallized, and they are so hard that they can only be abraded by rubbing one against another; hence the process of cutting and polishing is effected by means of finer diamond powder. The weight and value of diamonds are estimated in carats, one of which is equal to 3.174 grains troy; and the price of one diamond compared with another of equal colour, transparency, and purity, is as the square of the respective weights. In valuing diamonds, either rough or cut, the practice is to take the weights in carats, to square that weight, and then to multiply the product by such a rate of price as may correspond to the state and quality of the stone; thus, if a natural crystal of diamond be clear, without flaws, and of a favourable shape, the price by which the square of its weight should be multiplied is 27.; so that if the stone weigh 1 carat, its value will be 21.; if 2 carats, 2 × 2 = 4, and 4 × 2 = 8, or a stone of 2 carats is worth 87. A stone of 10 carats, in the same way, will give 10 x 10 = 100, and 100 × 2 = 2007., the value of a perfect rough diamond of this weight. The diamond, as Sir Isaac Newton conjectured from its high refracting power, is a combustible body. The researches of Lavoisier, and others, have shown that this gem is nothing more than pure carbon, and under the influence of the voltaic battery diamonds have recently been converted into coke. The plumbago, which is in the adjoining bay, and the coke but a short distance from it, differ only in physical condition; in chemical constitution they are similar to the diamond. The Koh-i-Noor diamond is to the east of the Transept, but it is thought the following account of it may be introduced in this place.

The diamond denominated the Koh-i-Noor, or Mountain (koh) of Light (noor), has long enjoyed both Indian and European celebrity, and has accordingly been the subject of traditionary fable, as well as of historical record.

According to Hindu legend, it was found in the mines of the south of India in the days of the Great War, the subject of the heroic poem, the Maha'bha'rata, and was worn by one of the warriors who was slain on that occasion, Karna, king of Anga: this would place it about four thousand years ago, or 3001 B. c. A long interval next makes it the property of Vikramaditya, the raja of Mjayin, 56 B. C., from whom it descended to his successors, the rajahs of Malwa, until the principality was subverted by Mohamedan conquerors, into whose hands it fell, with other spoils of infinite value.

Whatever may be thought of the legend which gives so high an antiquity to the Koh-i-Noor, we might expect some more trustworthy information when we come down so low as the beginning of the fourteenth century; Malwa having been invaded and overrun by the armies of Ala-addin, the sultan of Delhi, in 1306, who, according to the autobiography of the sultan Baber, acquired the jewel. That it did become the property of the sultanas of Delhi is little doubtful, but when or how is matter of some uncertainty, although the grounds of the difficulty have not hitherto been investigated.

In 1665 Mons. Jean Baptiste Tavernier, an enterprising and intelligent traveller, and an eminent jeweller, although Ecuyer, Baron d'Aubonne, visited India especially to purchase diamonds. His profession and his personal character seem to have recommended him to the favourable attention of the nobles of the court of Delhi, and bigot as he was, of Aurangzeb himself, by whose commands Mons. Tavernier was permitted to inspect and handle and weigh the jewels of the imperial cabinet. Amongst them was one which far surpassed all the rest in size and value. Tavernier describes it as rose-cut, of the shape of an egg cut in

two, of good water, and weighing 319 ratis, which, he says, is equal to 280 of our carats.

There is but little doubt that the diamond examined by Tavernier, in the Delhi Cabinet, was the Koh-i-Noor. Baber, the Mogul emperor, obtained a diamond, corresponding exactly with this, and it passed eventually into the possession of the ruling family of Kabul. Nadir Shah, on his occupation of Delhi in 1739, compelled Mohammed Shah, the great-grandson of Aurangzeb, to give up to him everything of value that the imperial treasury possessed, and his biographer and secretary specifies a peshkash, or present, by Mohammed Shah to his conqueror of several magnificent diamonds. According to the family and popular tradition Mohammed Shah wore the Koh-i-Noor in front of his turban at his interview with his conqueror, who insisted on exchanging turbans in proof of his regard. However this might have been, we need have little doubt that the great diamond of Aurangzeb, was in the possession of Mohammed Shah at the time of the Persian invasion; and if it was, it most certainly changed masters, and became, as is universally asserted, the property of Nadir Shah, who is also said to have bestowed upon it the name of Koh-iNoor. After his death, the diamond which he had wrested from the unfortunate representative of the house of Timur, became the property of Ahmed Shah, the founder of the Abdali dynasty of Kabul, having been given to him, or more probably taken by him, from Shahrikh, the young son of Nadir. The jewel descended to the successors of Ahmed Shah, and when Mr. Elphinstone was at Peshawur, was worn by Shah Shuja on his arm. When Shah Shuja was driven from Kabul, he became the nominal guest and actual prisoner of Runjet Sing, who spared neither importunity nor menace, until, in 1813, he compelled the fugitive monarch to resign the precious gem, presenting him on the occasion, it said, with a lakh and twenty-five thousand rupees, or about twelve thousand pounds sterling. According to Shah Shuja's own account, however, he assigned to

him the revenues of three villages, not one rupee of which he ever realized. Runjet was highly elated by the acquisition of the diamond, and wore it as an armlet at all great festivals. When he was dying, an attempt was made by persons about him, to persuade him to make the diamond a present to Jagannuth, and it is said that he intimated assent by an inclination of his head. The treasurer, however, whose charge it was, refused to give it up without better warrant, and Runjet dying before a written order could be signed by him, the Koh-i-Noor was preserved for awhile for his successors. It was occasionally worn by Rhurreuk Sing and Shu Sing. After the murder of the latter, it remained in the Lahore treasury until the supercession of Dhulip Sing, and the annexation of the Punjaub by the British Government, when the civil authorities took possession of the Lahore treasury, under the stipulations previously made, that all the property of the state should be confiscated to the East India Company, in part payment of the debt due by the Lahore government and of the expenses of the war; it was at the same time stipulated that the Koh-i-Noor should be presented to the Queen of England. Such is the strange history of certainly one of the most extraordinary diamonds in the world. After the Company became possessed of the gem, it was taken in charge by Lord Dalhousie, and sent by him to England in custody of two officers.

Corundum.-Varieties of this stone, exhibiting the different colours, are in this collection. This name is the Indian term applied by the natives to a large variety of those gems. The sapphire, from the ancient Greek name "sappheiros," is the most valuable of the corundums. This stone is scarcely inferior in hardness to the diamond. It invariably occurs crystallized when found in situ ; but it is often discovered in the beds of rivers as rounded pebbles, which, when broken, exhibit a very brilliant surface. These gems are compounds of alumina, lime, silica, and oxide of iron; and to the variations in quantity of the last sub