was entitled to a draught of every kind of liquor that was brought into the hall.

Why were bellows first invented?

Because they might imitate the action of the lungs and a hollow reed placed in the mouth of the blower, the latter being the first instrument employed for blowing a fire. Our common bellows appear to have been known to the ancient Greeks, and Roman lamps have been found in the form of bellows.

Why is it to be regretted that we know but little of the ancient construction of bellows?

Because more information on this subject would enlarge the knowledge we possess of the metallurgy of the ancients.

Strabo tells us, on the authority of an old historian, that Anacharsis the Scythian philosopher, invented the bellows, the anchor, and the potter's wheel; but this seems doubtful, as Pliny, Seneca, Diogenes, Laertius, and Suidas, only attribute the two last to him; and Strabo also remarks, that the potter's wheel is mentioned by Homer, who lived prior to the time of Anacharsis. It is, therefore, probable that the latter became acquainted with the invention on his travels, and having made it known to his countrymen, was looked upon as the inventor.-Beckmann.

Why are forge-bellows constructed with three boards? Because they are required to keep up a constant and unremitting stream of air through the fuel, to keep it in vivid combustion. Thus, the centre board is fixed, and furnished with a valve opening upwards, the lower board being movable with a valve also opening upwards, and the upper board being under a continual pressure by weights acting upon it. When the lower board is let down, so that the chamber between it and the middle board is enlarged, the air included between these boards being rarefied, the external pressure in the atmosphere will open the valve in the lower board,

and the chamber between the lower and the middle boards will be filled with air in its common state. The lower board is now raised by the power which works the bellows, and the air between it and the middle board is condensed. It cannot escape through the lower valve, because it opens upwards. It acts therefore, with a pressure proportional to the working power on the valve in the middle board, and it forces open this valve, which opens upwards. The air is thus driven from between the lower and middle boards into the chamber between the middle and upper boards. It cannot return from this chamber, because the valve in the middle board opens upwards. The upper board being loaded with weights, it will be condensed while included in this chamber, and will issue from the nozzle with a force proportionate to the weights. While the air is thus rushing from the nozzle, the lower board is let down and again drawn up, and a fresh supply of air is brought into the chamber between the upper and middle board. This air is introduced between the middle and upper board before the former supply has been exhausted, and by working the bellows, with sufficient speed, a large quantity of air will be collected in the upper chamber, so that the weights on the upper board will force a continual stream of air through the nozzle.-Lardner.

There are usually two blast-holes to conduct the stream of air from the bellows to the laboratory of the furnace, placed on opposite sides, but so angled that the streams do not impinge on each other. The bellows are commonly cylindrical, and their pistons are worked by a steam-engine.

Why are these bellows superior to the house-bellows ? Because the latter are constructed only with two boards, and have thus only an intermitting action, or blow by fits, the action being suspended while the upper board is being raised.

Why are German bellows made of wood superior to those in common use?

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Because the effect produced by them is stronger and more uniform, and they last longer. Some idea may be formed of this contrivance from the following sketch. The entire machine is composed of two boxes placed over each other, the uppermost of which can be moved up and down, in the manner of a lid with a hinge; but the sides of the upper box are sufficiently large to contain the lower between them, when raised to its greatest extent. Both are fastened together at the smallest extremity, where the pipe is inserted by a strong iron bolt. Thus, when the boxes fit each other with exactness, and the upper is raised over the under, which is immovable, the space contained within both will be increased: consequently, more air will rush in through the valve in the bottom of the lower one; and when the upper box is again pressed down, this air will be expelled forcibly through the pipe. The only difficulty is to prevent any portion of the air from escaping at any other part of the machine than the orifice of the pipe; and this is obviated by the simple contrivance of placing movable slips of wood at the inner sides of the uppermost box, which, by means of metal springs are pressed to the sides of the lower box, and fill up the intervening space. -Beckmann.

IRON.

Why is the use of iron believed to have been known in the earliest ages?

Because of its frequent mention in the bible: thus, Tubal Cain, who lived nearly 4,000 years before the commencement of the Christian era, was 66 an instructer of every artificer in brass and iron." (Gen. iv. 22.) and we read that Abraham took a knife to slay his son Isaac. (Gen, xxii. 10.) In these early times too, mention is made of shears and of shearing of sheep. (Gen. xxxviii. 12, 13.)

Why is this knowledge supposed to have been afterwards lost?

Because many of the ancient nations used stones, flints, the horns and bones of various animals, the bones and shells of fish, reeds and thorns, for every purpose in which the moderns now use edge tools of iron and steel.

Chronology informs us, iron was first discovered by the burning of Mount Ida, 1406 B. C. In England by the Romans, soon after the landing of Cæsar: first discovered in America, in Virginia, 1715: first cast in England, at Blackstead, Sussex, 1544.

Why was iron, at one period forbidden to be used by the Romans, except in agriculture?

Because they thought iron poisonous, and that wounds made with iron instruments healed with difficulty. Chemistry has, however, exposed this fallacy. Fourcroy says iron is the only metal which is not noxious, and whose effects are not to be feared. Indeed, its effects on the animal economy are evidently beneficial.

Why is iron the most useful of metals?

Because it becomes softer by heat, and has the capability of being welded to another piece of iron, so as to form one entire mass: and this may be done without rivets, solder, or melting either of the pieces. No other metal possesses this singular property, except platinum.

An iron wire only one-tenth of an inch in diameter, will carry 450 pounds without breaking. A wire of tempered steel of the same size will carry nearly 900 pounds.-Black.

Why has the iron trade of Great Britain increased so extraordinarily since the year 1750?

Because then pit-coal began to be generally used for extracting cast iron from its ores. In 1740, England and Scotland did not possess more than 59 furnaces, producing 17,000 tons; whereas in 1827, they had increased to 284 furnaces, producing 690,000 tons. A

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writer in a French Journal, therefore, describes pitcoal as "the prime element of the manufactures and the wealth of England." The mean annual amount of the exportation of iron and steel from this country, in bars and wrought works, is from 1,200,000l. to 1,500,000l. The annual quantity of iron manufactured in Great Britain is 690,000 tons.

In the great iron works, the ore, broken into small pieces, and mixed with lime or some other substance to promote its fusion, is thrown into the furnace; and baskets of charcoal or coke, in due proportion, are thrown in along with it. A part of the bottom of the furnace is filled with fuel only. This being kindled, the blast of the great bellows is directed on it, and soon raises the whole to a most intense heat: this melts the ore immediately above it, and the reduced metal drops down through the fuel and collects at the bottom. The rest sinks down to fill up the void left by the consumed fuel, and this, in its turn, comes next in the way of the bellows, and is also reduced. More ore and fuel are supplied above, and the operation goes on till the melted metal at the bottom, increasing in quantity, rises almost to the aperture of the blast; it is let out by piercing a hole in the side of the furnace, and then forms what are called pigs of cast iron.-Parkes.

The Butterley iron-works are amongst the most important in this country. Here are three furnaces, each capable of producing thirty-five tons of pig iron, or crude cast iron, per week. The blast furnaces are about forty feet high, and about thirteen in the largest diameter. When charged, they contain about 3,500 cubic feet of iron stone, coke, and lime-stone, which produce one ton of melting iron. When heated, they are kept in a state of intense heat for many months or years, without intermission, and are constantly supplied at the tops with materials. Blast cylinders, worked by a steam-engine of 80-horse power, continu

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