. The universal assistant, and complete mechanic : containing over one million industrial facts, calculations, receipts, processes, trade secrets, rules, business forms, legal items, etc., in every occupation, from the household to the manufactory. lillfd with sand or clay,wliich is rammed down hard by iikmiis of a tampin;/ bar, formod of hard■wood, or of iron with a copper tip, wliicli is ptriick witli .1 heavy many instances lamentable accidents have occurred by the use of iron orsteel tamping bars causing premature explosions by stril/ing fire against thesides of the hole ; hence
. The universal assistant, and complete mechanic : containing over one million industrial facts, calculations, receipts, processes, trade secrets, rules, business forms, legal items, etc., in every occupation, from the household to the manufactory. lillfd with sand or clay,wliich is rammed down hard by iikmiis of a tampin;/ bar, formod of hard■wood, or of iron with a copper tip, wliicli is ptriick witli .1 heavy many instances lamentable accidents have occurred by the use of iron orsteel tamping bars causing premature explosions by stril/ing fire against thesides of the hole ; hence tho necessity for the use of wooden, or copper-tipped tamping bars, which never, under any circumstances, strike fire byconcussion against the rocks. Tho hole being tamped, tho projecting end ofthe safety-ftrsoi;? ignited, and ■while tho combustiblo matter which fills thointerior of t^.e fu?o is slowly burning towards tho end inserted in thapowder, the men ■ to a sheltered place to avoid danger from tho (ly-ing rocks projected by the explosion. As nearly as CJiu bo computed thaamount of powder employed iu blasting sliould be just enough to split thorock ; in some cases this is effected by the action of fire without Fig. 23.—Timbering of Mikks on the Comstook In using nitro-glyceriue for blasting in mines, tho advantages are, thatit requires a smaller hole than gunpowder; it disi)euses witli tamjiing, aawater only is used (to fill the holes), in which it is easily ignited ; it is muchcheaper than gunpowder, and has, taken volume for volume, twelve tinieagreater explosive force. See page iMVi Lastly, it can, with j^ropor ]), be easily manufactured on or near the s^wit where it is requiredlor use, the main conditions being, that syrup of glycerine shall be slwwlj 954 QUARTZ MACHINEET. dropped in a compound formed of equal quantities of nitric and sulp^.iaricjacids contained iu a strong vessel surrounded by ice, witii a thorough agita-
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Keywords: ., bookcentury1800, bookdecade1870, booksubje, booksubjecttechnology
