2096. Crown-glass, as it can be manufactured nearly equal to sheet-glass in strength, is now generally preferred to it for horticultural purposes, as it prevents the formation of lenses. Crown-glass cannot, however, be made so large as the sheet-glass, the largest crown-glass being only about 9 in. wide, and from 20 in. to 22 in. long; whereas the sheet-glass may be had 33 in. long, and 12 in. wide, or even larger, if requisite.