Figure 103 is a section through a portion of the furnace front and shield showing all of the principal parts. This shield consists essentially of a very thin tank, about 2-1/2 in. between walls, and filled with water. Like other shields it is fitted with an adjustment, that it may be raised and lowered as the work demands. The tank having an open top, the water as it absorbs heat from the flame will simply boil away in steam; and only a small amount will have to be added to make up for that which has evaporated. The water-feed pipe shown at _F_ ends a short distance above the top of the tank so that just how much water is running in may readily be seen. An overflow pipe is provided at _O_ which aids in maintaining the water at the proper height, as a sufficient quantity can always be permitted to run in, to avoid any possibility of the shield ever boiling dry; at the same time the small excess can run off without danger of an overflow. The shield illustrated in Fig. 104 has been in constant use for over two years, giving greater satisfaction than any other of which the writer has known. It might also be noted that this shield was made with riveted joints, the shop not having a gas-welding outfit. To flange over the edges and then weld them with an acetylene torch would be a far more economical procedure, and would also insure a tight and permanent joint. The water-cooled front shown in Fig. 105 is an absurd effort to accomplish the design of a furnace that will provide cool working conditions. This front was on a bolt-heating furnace using hard coal for fuel; and it may be seen that it takes the place of all of the brickwork that should be on that side. Had this been nothing more than a very narrow water-cooled frame, with brickwork below and supporting bricks above, put in like the tuyeres in a foundry cupola, the case would have been somewhat different, for then it would have absorbed a smaller proportion of the heat. A blacksmith who knows how a piece of cold iron laid in a small welding furnace momentarily lowers the temperature, will appreciate the enormous amount of extra heat that must be maintained in the central portion of this furnace to make up for the constant chilling effect of the cold wall. Moreover, since there would have been serious trouble had steam generated in this front, a steady stream of water had to be run through it constantly to insure against an approach to the boiling point. This is illustrated because of its absurdity, and as a warning of something to avoid.