Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . cylinder. It is now spread out into a sheet by pressing the same on the flatting-stone, by means ofa small block of elder-wood, fixed on an iron bar m. The temperature at which the flatting is per-formed is such that the operation does not occupy more than a minute. Two improvements have been introduced in this operation. One consists in making part of thefloor of the compartment a to consist of a movable stone about 10 inches in diameter, on which the 2170. />? i. cylinder is place
Appletons' cyclopaedia of applied mechanics: a dictionary of mechanical engineering and the mechanical arts . cylinder. It is now spread out into a sheet by pressing the same on the flatting-stone, by means ofa small block of elder-wood, fixed on an iron bar m. The temperature at which the flatting is per-formed is such that the operation does not occupy more than a minute. Two improvements have been introduced in this operation. One consists in making part of thefloor of the compartment a to consist of a movable stone about 10 inches in diameter, on which the 2170. />? i. cylinder is placed. It is gradually exposed on all sides to the action of the fire by causing the stoneto revolve on its axis, and thus the objection to the previous plan is avoided, where one side of eachcylinder became so much hotter than the other. Annealing usually requires from 24 to 36 hours. From the annealing-oven the sheets are taken tothe warehouse, where they are smoothed, polished, assorted, and cut into panes of the required GLASS, MANUFACTURE OF. 43 dimensions. The former method of grinding and polishing sheet-glass by imbedding the sheets inplaster of Paris proved inadequate to remove the defects in the glass consequent upon the mode ofmanufacture. The chief of these was the undulating or wavy appearance of the surface, calledcockles, which was attributed to the difference of diameter between the inner and outer surfaces ofthe cylinder, and which caused objects seen through the glass to be distorted. Notwithstanding theglass was made very thick, after the superficial ro
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Keywords: ., bookauthorbenjaminpark18491922, bookcentury1800, bookdecade1880
