Popular science monthly . A sharp blow with a hammer may crackthe glass but will not shatter it into splinters. glass, because none would fly. A stonei irown against it will bounce back like agolf ball. When struck a powerful blow, aswith a hammer, for instance, itwill crack into hair lines, asshown in the accompa-nying illustration, butthere will be no showerof flying glass or splin-ters. Furthermore,these hair-line cracksleave the surface abso-lutely smooth. The secret of itsstrength is a sheet ofwhite, transparent cel-luloid, t w e n t y - o n ethousandths of an inchthick, which is placedbe
Popular science monthly . A sharp blow with a hammer may crackthe glass but will not shatter it into splinters. glass, because none would fly. A stonei irown against it will bounce back like agolf ball. When struck a powerful blow, aswith a hammer, for instance, itwill crack into hair lines, asshown in the accompa-nying illustration, butthere will be no showerof flying glass or splin-ters. Furthermore,these hair-line cracksleave the surface abso-lutely smooth. The secret of itsstrength is a sheet ofwhite, transparent cel-luloid, t w e n t y - o n ethousandths of an inchthick, which is placedbetween two pieces ofglass. The glass andcelluloid are simplywelded together underhigh temperature andtremendous pressure,the resultant being asolid sheet possessing all thetransparency of the best plateglass, combined with thestrength of a sheet of metal. • I A boiler can be blown clean in six minutes. If cleaned oncein every six hours it will increase five per cent in efficiency Preventing Boiler Troubles byMechanical Cleaning THE shortcomings and diffi-culties connected with thehand-cleaning of modern s
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Keywords: ., bookcentury1800, bookdecade1870, booksubjectscience, bookyear1872
