In the repair of leaden vessels exposed to the action of heat, peculiar advantages are offered by autogenous soldering. By the old method, the holes which are so often caused in the bottoms of these vessels, either by the action of sudden flames, or by deposits that form on their surface, can be stopped only when they are not of too large dimensions, by making what are called weldings of pure lead. The cases in which this mode of repair is available, are very limited, and whenever it is impracticable, the boilers must be taken down, the lead changed, and then reset; thus occasioning considerable expense and an interruption to business. By the new method, nothing is easier than to apply pieces to the bottom or sides of the vessels, whatever be the size of the holes, and thus the whole of a boiler may be renewed piecemeal. By this plan, too, the old lead remains uncontaminated with solder, and consequently will yield a pure metal to the melting-pot. The great ductility of lead, which, in many cases, is one of its most valuable qualities, is, however, an inconvenience when instruments or utensils are required of considerable strength. At the same time, there are circumstances where this metal alone can be employed, on account of the manner in which it resists chemical action. By constructing vessels or instruments of iron, zinc, or wood, and covering them with lead, utensils can be formed that will resist pressure and blows, and most chemical agents, as well as if they were made of solid lead. Such vessels are required in the preparation of soda, and other gaseous waters; in the distillation or evaporation of acid or alkaline solutions; and for many other purposes. Another application that deserves especial notice is that of lining common barrels with thin sheet-lead. These vessels would be of great utility in chemical factories, more particularly in the construction of Woulf’s apparatus, and other pneumatic instruments, to which greater dimensions could be given by this means; but they could be employed with singular advantage in the transport of acid and alkaline liquids by sea and land. Sulphuric and muriatic acids are transported in stone bottles, or glass carboys placed in baskets, which, however carefully packed, are liable to be broken, not only with the loss of the acids, but with danger to surrounding bodies. We are told of two French ships that perished at sea on a voyage to the colonies, in consequence of the breaking of some bottles of sulphuric acid.