and out of that he pays all the workmen, but the materials which are necessary are provided for him.

The only differences between this tin-plate works and those of Johann-Georgen-Stadt, are, that after putting all the sheets into the tin bath for a few minutes, they are taken out and returned altogether to the bath when they are cold.

They use rather more tin in Bohemia. They work up to 21 lbs. for 300 sheets, but the sheets are larger, and they pass them through twice; they make 1218×95.

TIN-PLATE WORKS IN SWEDEN.

At Joahnessors, about five miles from Forsmark, there is a tin-plate and a nail manufactory.

They do not employ rolls to make sheets suitable for tinplates; they have tried them, but from prejudice, or some other reason, they consider the method of forging them out under the hammer to be most advantageous.

These works were established about 1739; they brought from Saxony and Bohemia workmen who understood the manufacture; in 1767 there were seven of them who superintended all the work.

The iron is brought from the forge of Forsmark in long square bars, the workmen divide them into as many pieces as they require to produce sheets of such or such a size, they manage this by marking off each division with chalk, the bars are then placed in a reverberatory furnace which is continually burning to make them red hot, then they are taken out and "presented" to the shears, which is driven by water power, and which divides them to the size desired.

They have the same sort of heavy hammer at all the works in Sweden, under which all these pieces are beaten out one by one; after having been heated in the same reverberatory furnace, they are enlarged by hammering to double their original size, and then they are bent one upon the other.

During the process of forging out the pieces to size, the number of sheets is increased at each beating, so that, having

started with one, they finish with ninety-six, which they hammer together; however, they take care not to overheat the sheets because they would then run the risk of being welded together.

In order to avoid this inconvenience when the bundle is taken out of the furnace and before it goes to the hammer, they take care to place it (the bundle) on the ground, the workman holds it vertically with a pair of tongs, then a little water is thrown all over it and coal dust after that, which introduces itself between the sheets and effectually prevents the welding.

They are careful to remove the upper and under sheets, which are placed in the middle of the bundle; they also do the same with the inside sheets after shearing.

After every beating, they are obliged to cut a great deal off the sides.

They manufacture sheets of several sizes, which are heated eight times in the furnace and subsequently placed eight times under the hammer before they are completely finished.

It is possible in one week to forge with one hammer 12 schiffund of iron and to hammer out 4320 sheets, which weigh no more than 8 schiffund, the shreds (shearings) which result are about 3 schiffund, so that, on this quantity, there is 1 schiffund of loss.

In 1766 they only produced 190 schiffund at Joahnessors, although the proprietor had liberty to make up to 300 schiffund.

When the sheets have been finished under the hammer, and after being cut to size in the hand shears, they are carried away to the stove for pickling, which is done in the same way as in Bohemia.

The tin-pot is of cast iron, and of the same dimensions at the top and bottom of the pot, the inside measure is 181 inches long × 16 inches wide and 16 inches deep: it is placed over a furnace fixed in masonry.

The surface is constructed with four inclined planes (one on each side), and the whole are covered with plates of iron

exactly fitted to the tin pot, so that any surplus tin running over the said planes passes back again to the tin-pot.

This cauldron (the pot) is generally partly full of water, because when they have finished tinning, they add fresh tin and tallow, and cover them up with water, and it all remains cold till the day when it (the pot) is again required for use. When they start again, a fire is lighted under the pot, fifteen or sixteen hours beforehand, as in Bohemia.

English tin is employed, to which they add about 2 lbs. of copper to every 17 or 18 lisgund of tin.

CHAPTER VII.

A DESCRIPTIVE ACCOUNT OF THE SEVERAL PROCESSES WHICH ARE USUALLY PURSUED IN THE MANUFACTURE OF THE ARTICLE KNOWN IN COMMERCE BY THE NAME OF TIN PLATE, BY SAMUEL PARKES, ESQ., IN A LETTER TO B. NAYLOR, ESQ., FEBRUARY 20, 1818.

As the processes in this manufacture are more numerous and complicated than is generally imagined, it may be advisable to preface the account with an enumeration of some of those properties of tin which will be most likely to explain the rationale of the principal operations.

Tin has a great affinity for several of the other metals, particularly for zinc, mercury, copper, antimony, lead, and iron, and owing to these affinities, its employment in thẹ arts is very considerable.

Tin with zinc forms a metal of close grain, very useful for many purposes, especially for the formation of pewter. The zinc is found to impart great hardness to the tin, without lessening its ductility.

The combination of mercury and tin, in which the tin is dissolved by the mercury into a very soft amalgam, is largely employed, as is well known, in silvering the backs of mirrors, and for other purposes in the arts. An amalgam of tin of greater consistence was formerly in use in the museums of Paris for closing the mouths of glass bottles containing sundry curious and valuable preparations.

Copper is also alloyed with tin for various purposes of manufacture. This metallic mixture is employed in working what are called bronze statues; for casting bells, and pieces of artillery, and also for the fabrication of medals and medallions. In some of these cases the tin is mixed with

copper, on account of its property of rendering the copper more fusible, and this was probably the reason why the Ancient Romans used that metal in the greater part of their brass coinage. It is owing to the affinity of tin for copper, that vessels of capacity, made with the latter metal, for culinary and other purposes, are so readily covered with a coating of tin, to preserve them from the action of substances which would not fail to erode copper if unprotected by some such covering. The affinity of tin for copper is farther exemplified by the process of whitening pins, which is effected by boiling the pins with granulated tin, in a lie made with alum and tartar.

A useful alloy is likewise formed by the mixture of tin and antimony. This metallic compound is very white, extremely hard, and will bear a very fine polish. On these accounts it is employed in making specula for telescopes, and also for the manufacture of rolled plates to engrave music upon.

The next metal which I have mentioned as uniting readily with tin is lead. This metal will combine with tin in any proportion, and in most proportions the lead acquires a greater degree of fusibility by its union with the tin. It is this alloy which forms plumbers' solder, but that compound is prepared with different proportions of tin, according to the purpose for which it is intended. The article called tin foil, used for lining tea-caddies, for coating electrical jars, and for other purposes, is also made from a mixture of these two metals.

But what is more relevant to the subject of this paper, is the chemical affinity which subsists between tin and iron. One of the strongest proofs of this affinity is derived from the circumstances that even cast iron may be tinned in the same manner as wrought iron.

Of late years, cast iron saucepans, and pots of a large size, are permanently tinned on their inner surfaces, to prevent the liquors which are boiled in them from acquiring any stain by a partial dissolution of the iron. Many other articles, such as bridle bits, common stirrups, small nails, &c., are now