It will be seen that the process adopted in this machine follows as closely as possible the various stages of hand blowing, but that the mechanical movements of the machine replace the laborious and difficult technique of the blower. One such machine is capable of producing as many as 120 bottles, each weighing 1¾ lbs., per hour, but this is accomplished only by having some of the moulds in duplicate and so arranged as to come into use alternately. The machine itself is attended by one “moulder,” who operates the levers, and by a youth, who carries the finished bottles to the annealing kiln, while, of course, the services of a gatherer are also required. The appearance of a bottle works equipped with these machines is in striking contrast to that of a hand-blowing works, where the stages around the working-holes are crowded with men doing arduous work under very severe conditions of temperature and atmosphere. Finally, it must be pointed out that the use of the Boucher machine is by no means confined to the production of the cheapest kinds of bottles, but that it has shown itself especially well suited to the production of champagne and other bottles that are required to withstand a high internal pressure, the machine-made bottles showing excellent results under pressure tests. The machine is also used for the production of moulded glass-ware of white glass, since it can be adapted to the production of any kind of glass vessel that can be produced by blowing into a mould. The annealing of bottles was formerly carried out in large chambers or kilns of very simple construction, in which the bottles were stacked as made, the kiln being previously heated to the requisite temperature: when full, the kiln was closed up in a rough temporary manner and allowed to cool naturally, thus annealing the bottles stacked within it. In this branch of glass-making also, however, the continuous annealing kiln has superseded the older kinds, and continuous kilns are now almost universal in bottle-making. In these kilns, which consist of long tunnels, kept hot at one end and having a gradually decreasing temperature as the other end is approached, the bottles are stacked on trucks which are slowly drawn through the kiln from the hot to the cold end. At the cold end the trucks are unloaded and are then returned, by an outside route, to the charging end, but of course the bottles cannot be stacked on the truck until it has actually entered the hot end of the tunnel and acquired the temperature there prevailing. In a slightly different form of kiln, the bottles are carried down the kiln on a species of conveyer belt formed of iron plates, but the principle of all these appliances is similar even when used for very different kinds of glass.