the condition of every worker in the parent-land; and they have given an immense impulse to our home industry. The importance of gold, merely as a material of manufacture, may be estimated from the fact that in Birmingham alone a thousand ounces of fine gold are worked up every week; and that ten thousand ounces are annually used in the porcelain works of Staffordshire. Whatever diminishes the risk to life or health, in any mechanical operation, or any exertion of bodily labour, lessens the cost of production, by diminishing the premium which is charged by the producers to cover the risk. The safety-lamp of Sir Humphry Davy, by diminishing the waste of human life employed in raising coals, diminished the price of coals. The contrivance is a very simple one, though it was no doubt the result of anxious and patient thought. It is a common oil-lamp, in which the flame is surrounded with a fine wire-gauze. The flame cannot pass through the gauze; and thus if the destructive gas of a coal-mine enters the gauze and ignites, the flame cannot pass again out of the gauze, and ignite the surrounding gas. Sometimes the inner flame burns with a terrible blue light. It is the symptom of danger. If the lamp were an open flame the fire-damp would shake the pit with one dreadful explosion. The safety-lamp yields a feeble light; and thus, unfortunately, the miner sometimes exposes the flame, and perishes. The magnetic mask, which prevents iron-filings escaping down the throats of grinders and polishers, and thus prevents the consumption of the lungs, to which these trades are peculiarly obnoxious, would diminish the price of steel goods, if the workmen did not prefer receiving the premium in the shape of higher wages, to the health and long life which they would get, without the premium, by the use of the mask. This is not wisdom on the part of the workmen. But whether they are wise or not, the natural and inevitable influence of the discovery, sooner or later, to lessen the cost of production in that trade, by lessening the risk of the labourers, must be established. The lightning conductor of Franklin, which is used very generally on the Continent, and almost universally in shipping, diminishes the risk of property, in the same way that the safety-lamp diminishes the risk of life; and, by this diminution, the rate of insurance is lessened, and the cost of production therefore lessened. [Illustration: Franklin medal.]