Publisher's Synopsis
This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1849 edition. Excerpt: ... view of the annealing arches, showing three sets of pans heating each with a separate fire, wita the same cylindrical brick arches and cast-iron doors A lear is the term given to an arch, or oven, open at both ends. Each lear has a small furnace at the receiving end or side nearest the large Glass furnace; the hot end may be termed the receiving end, and the cooler the discharging end; the latter terminates with a chimney, and the hot end is kept at a temperature just short of a melting heat. The caloric is sustained by oven-burnt coke, which imparts, decidedly, the most regular heat for annealing, and is the freest from smoke, the carbon of coal smoke being generally injurious to the colour of the Glass. There are from two to four of these semi-cylindrical arches, built side by side; on the floors of these are placed iron pans to receive the manufactured goods, which travel upon a miniature railroad gradually downward from the heated to the cooler end, a distance of about sixty feet: one-fourth of the length of this distance is arched, and leads into an air-tight receiving or sorting room, from which the goods are ultimately removed. If there be two or more lears, or arches, in one house, there should be various degrees of heat in each; the highest being intended for strong goods for cutting, the medium for the ordinary run of table Glass, and the lowest for vials or light lamp glasses. The time for annealing varies from six to sixty hours, the weighty articles requiring the most heat and time. The best arrangements for annealing may be foiled, should the Glassblower unnecessarily lose time after finishing the work; as the hotter the goods enter the arch, the better; on this account, the large goods receive a final reheating at the...
