MINER'S TOOLS.

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is used to break larger pieces of rock or mine. A miner's shovel is pointed, so as to penetrate the coarse and hard fragments of minerals and rocks. All these tools should be well steeled and tempered, and kept in good repair.

Besides these, the miner requires the following blasting tools: a hand-drill, which is a bar of iron or steel, edged at one end and

headed at the other-both well hardened and tempered; the scraper, a small ron rod with a hook on one end, to take the bore-meal out of

the hole; and a copper needle, which is a simple wire one-fourth of an inch thick, somewhat tapered at one end. The tamping-bar is a bar of round iron, with a groove to fit the needle.

The erection of a furnace is a very complicated and hazardous task.

The stack is always a piece of splendid masonry, requiring the most compact and heat-resisting stones. The engraving on page 111 exhibits

IRON MANUFACTURE.

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a front view of a furnace stack, as they are ordinarily built-there being little difference in their external appearance, between charcoal and anthracite furnaces; this figure exhibits the prominent features of both.

Charcoal furnaces are built upon one general principle, but vary materially in size and appearance, as well as in their interior structure, according to the kind of ore and fuel, and similar circumstances governing their operations. The interior of the furnace-stack is lined with a wall of fire-brick, or else with fire-grained white sandstone, both of which are well adapted to resist the extraordinary heat to which it is exposed. The lining is situated a few inches from the main stack, the space between being filled in with fragments of stone, sand, and occasionally coarse mortar. This serves to protect the stack from the decomposing effects of the heat. The furnace stack is, moreover, secured from expansion by strong iron girders imbedded in it, as indicated in the engravings. The stack is generally surmounted with an iron or wooden-railing. The height of the furnace, of which the engraving on page 112 is a sketch, is thirty-five feet. The hearth measures five and a half feet from the base to the boshes; its width at the bottom is twenty-four inches, and at the top thirty-six inches. The boshes are nine feet and a half in diameter, and measure from the top of the crucible four feet, thus giving a slope of about 60°. The tryeres are twenty feet above the base of the hearth. The blast is conducted through iron pipes, laid below the bottom-stone of the hearth, into the tryeres. There is little difference, either in the interior or outward structure, between charcoal and anthracite furnaces; but to render our treatise as complete as possible, we append a view of the cross-section of the latter-that of Dr. Eckert, situated near Reading. (The Doctor is one of the most experienced, intelligent, and practical men connected with the iron-trade of this State. He formerly represented the fourteenth district in Congress-the largest and most important one in the Union. He is at present Director of the United States Mint, in Philadelphia, and we know of no man more thoroughly versed in all the practical intricacies and political economy of the coal and iron trade of Pennsylvania.) The height of this furnace is thirty-seven and a half feet; the top six feet in diameter; hearth, five feet high; tryeres twenty-two inches above its bottom; hearth, five feet square at the base, and six feet at the top; boshes inclined 671°, or six inches to the foot, and measure fourteen feet at their largest diameter. Many of the anthracite furnaces receive their charges of ore and fuel by a very ingenious contrivance,

which was first introduced at the Crane works, near Easton, and is applied at Phoenixville, Safe Harbor, and other places. A reservoir of water is put upon the trunnel-head bridge, where it is kept filled by means of force-pumps from the blast-engine. An iron chain suspended over a pulley carries one or two buckets of sheet iron, sufficiently heavy, when filled, to balance a charge of ore or coal. When

either of these is loaded below, the filler turns a stop-cock, and fills the water bucket or barrel, which descends and lifts up the charge. A valve in the botton of the water-cask, which is opened by a simple arrangement, permits the water, when it arrives at the proper place, to escape. The platform containing the ore or coal, relieved from its burthen, is charged with empty boxes or barrows, after which it