The annealing of industrial glass articles is briefly outlined. The temperature of various types of machine made glass hollow ware when leaving the machine and during cooling in air was measured by the method of mixtures. The former temperatures ranged from 669o to 759oC. The producer gas fired lehr is described and compared with a fully insulated electrically heated lehr. Mainly owing to the absence of insulation the producer gas fired or oil fired lehr cost 120s per day ( 250gal of oil fuel) to anneal 35 tons of glass, whereas the electric lehr costs 21s per day. The electric lehr is described in detail. Novel features include removable slag wool insulation held in trays at the feed end and circulation of air of adjustable temperature through the rapid cooling section. A heat balance is calculated in two cases. Two further applications of electricity are described: (1) the reheating of blown glass tumblers prior to fire polishing of the edges and subsequent annealing and (2) the controlled reheating of milk bottles during the enamelling of advertising matter thereon.
