=The Sheffield Silver Plating Process.=--It has been already shown that the superimposition of silver and gold on baser metals was not an unknown thing, and that many old statutes exist to prevent such wares being substituted for solid gold and silver plate. These earlier processes mainly depended on washing or laying on successive sheets or foils. The Boulsover process consisted in cutting off from a solid bar of copper a rectangular piece some three inches wide, twelve inches long, and about one inch in thickness. This was pure soft copper and easy to work. Later an alloy was made with the addition of a sixth part of brass making the base or body harder. One side of this copper block is carefully filed, extreme cleanliness being employed to exclude any dirt from the surface. A silver sheet of slightly lesser dimensions, after being made thoroughly flat and kept perfectly clean on one side, is laid on the copper with the two prepared surfaces fitting upon each other. The silver was about a quarter of an inch in thickness. Over the silver is laid a piece of sheet iron the exact size of the silver. The three sheets are then tightly bound together by means of iron wire. The whole is then put into a furnace until it is red hot; at the exact moment when it is considered by the skilled workmen that the two metals had properly fused together the block was carefully taken from the furnace and put aside for cooling. It is obvious that if the workmen were careless and did not by constant practice know the correct length of time to allow the operation to continue in the furnace the result would have been a failure. The silver, instead of exactly fusing with the copper, would run over the edges and leave patches where the two metals had not properly adhered. It is the same in old processes such as the tempering of a sword. There are no exact rules, the craftsman must have a sure eye and be quick to act at a second's notice. Those who have witnessed the cabinet-maker in the exactitude with which he commands his mastery over glueing parts, as is experienced in the manufacture of air-craft parts, know that given perfect conditions of temperature and glue of indubitable character the parts cannot be separated. Similarly in the Sheffield plating the silver adhered to the copper base and remained a component part and not a layer likely to be disturbed by future bending or hammering.