immediately from this they are put into the pot of tallow above mentioned. This pot has pins fixed within it, in such a manner as to prevent the plates from touching each other; and this part of the process is conducted in the following manner. When the wash man has passed five of the plates through the melted tin, and from thence into the pot of tallow above mentioned, a boy takes out one of them and puts it into the empty pot to cool, and the wash man puts in the sixth plate. The boy then takes out a second plate, and lays it to cool likewise, when the man puts in his seventh, and so they go on, in this regular manner, until the whole of the parcel is finished. In consequence of the plates being immersed in the melted tin in a vertical position, there is always, when they have become cold, a wire of tin on the lower edge of every plate, which is necessary to be removed, and this is done in the following manner. A boy, called the list boy, takes the plates when they are cool enough to handle, and puts the lower edge of each, one by one, into the list pot, which is the vessel that was before described as containing a very small quantity of melted tin, and the same as that which I have marked No. 5. When the wire of tin is melted by this last immersion, the boy takes out the plate, and gives it a smart blow with a thin stick, which disengages the wire of superfluous metal, and this falling off, leaves only a faint stripe in the place where it was attached. This mark may be discovered on every tin plate which is exposed for sale-the workmen in the manufactory call it the list. Nothing now remains but to cleanse the plates from the tallow. This is done by means of bran, and as they are cleansed they are put into strong wooden boxes or boxes of sheet iron, made exactly to fit them; and this completes the whole business. Each box contains a determinate number of plates, and the following table will show the different sizes of tin plate which are made in Great Britain, and the marks by which each kind is known in commerce. CHAPTER VIII. PAPER ON THE MANUFACTURE OF TIN-PLATES, BY MR. EBENEZER ROGERS; TAKEN FROM THE REPORTS OF THE SOUTH WALES INSTITUTE OF ENGINEERS, 1857. AFTER a brief and very imperfect reference to the introduction of the trade from Bohemia Mr. Rogers proceeds to state that About the year 1720, works for the manufacture of tin-plates were established at Pontypool, and these seem to be the earliest of such works in England, as were permanently successful. In 1728, John Payne invented a process for rolling, and this seems to have at once led to the use of flat or sheet rolls for the manufacture of iron for tin-plates; but it is very remarkable that no further progress was made in this discovery of rolling iron until 1783, when Henry Cort invented the grooved rolls. This discovery was not appreciated for some years. Mr. Reynolds, of Ketly, erected Cort's rolls in 1785. In 1790, Henry Cort was engaged by Mr. Richard Crawshay to erect the mills at Cyfarthfa, and soon after this important improvement in the iron manufacture was generally adopted. The writer purposes to give in this chapter a short résumé, first, of the process of cleaning and tinning the iron plate, and afterwards of the methods of preparing the iron for this purpose. The affinity of iron for tin is much greater than generally supposed. The points at which the metals cohere is no doubt an actual alloy, and advantage is taken of this by the manufacturers of iron articles for domestic use, such as bridle bits, common stirrups, small nails, &c. When the iron, whether wrought or cast, is perfectly clean and free from rust, and brought in contact with melted tin, at a high temperature, an alloy seems to be at once formed, protecting the iron from oxidization whilst the tin lasts. Many different ways of tinning iron articles of small size are adopted by the manufacturers. One of the common methods of coating bridle bits and small ware with tin, in South Staffordshire, is-to clean the surface of the articles to be tinned by steeping them for sufficient time in a mixture of sulphuric and muriatic acids, diluted with water; then to wash them well with water, and, taking great care that they do not rust, at once placing them in a partially closed stoneware vessel (such as a common bottle), which contains a mixture of tin and muriate of ammonia. This vessel must then be placed on a smith's hearth, duly heated, and frequently agitated to secure the complete distribution of the tin over the iron. The articles when thus tinned are thrown into water to wash away all remains of the sal-ammoniac; and lastly, cleaned in hot bran or sawdust to improve the appearance for sale. The method of cleaning and preparing the iron for tinning has undergone many changes in the past century. About 1720, the plan of cleaning was to scour the plates with sand and water, and file off the rough parts, then to cover them with resin, and dip them in the melted tin. About 1747, the plates were, after being cold rolled, soaked for a week in the lees of bran which had been allowed to stand in water about ten days, to become by fermentation sufficiently acid, and then scoured with sand and water. In 1760, the plates were pickled in diluted muriatic acid before annealing, and cleaned with diluted sulphuric acid, after being taken out of the bran lees. An improvement of great importance in this process was made about 1745, the inventor seems to have been Mr. Mosely, who carried on tin-plate works in South Staffordshire. This invention was the use of the grease-pot, and in this department little, if any, improvement has since been made. The plan was introduced into South Wales in 1747, by Mr. John Jenkins, and his descendants are still amongst the principal manufacturers in the trade. The process of cleaning and tinning at some of the best works now is as follows: when the sheet iron leaves the plate mill, after separating the plates and sprinkling between each plate a little sawdust (the effect of which is to keep them separate), they are immersed, or, as tech-. nically termed, "pickled" in diluted sulphuric acid, and after this, placed in the annealing pot and left in the furnace about twenty-four hours; on coming out the plates are passed through the cold rolls; after passing the cold rolls, the plates seem to have too much the character of steel, and not sufficiently ductile; to remedy this they are again annealed at a low heat, washed in diluted sulphuric acid, to remove any scale of oxide of iron, and scoured with sand and water; the plates in this state require to be perfectly clean and bright, and may be left for months immersed in pure water without rust or injury, but a few minutes' exposure to the air rusts them. When perfectly clean they are taken to the tinman's pan, which is full of melted grease. In this the plates are immersed, and left there until all aqueous moisture upon them is evaporated, and they are completely covered with the grease; from this they are taken to the "tin pot and then plunged into a bath of melted tin, which is covered with grease; but as in this first dipping the alloy is imperfect, and the surface not uniformly covered, the plates are removed to the dipping or wash-pot; this contains a bath of melted tin covered with grease, and is divided into two compartments; in the larger compartment the plates are plunged, and left sufficiently long to make the alloy complete, and to separate any superfluous tin which may have adhered to the surface; the workman takes the plate and places it on the table, and wipes it on both sides with a brush of hemp; then, to take away the marks of the brush, and give a polish to the surface, he dips it in the second compartment of the wash-pot. This last always contains the purest tin, and as it becomes alloyed with the iron it is removed on to the first compartment, and after to the "tin pot." The plate is now removed to the "grease-pot;" this is |