45< 



POPULAR SCIENCE MONTHLY. 



to considerable distances from a vessel in a raging sea, so that the 

 oil, as it diffuses, may still the waters in her course; while sound- 

 ing-lines may be thrown far in advance of a vessel while she is still 

 under way, and the soundings taken without her laying-to. 



Inclosed in shallow tin boxes, which are fixed by lead strips to 

 the top of the rail, explosives are used as torpedoes in the railroad 

 service to give warning, by the report of their explosion as an 

 engine runs over them, that another train is on the same track 

 and but a short distance ahead, and by this means collisions in 

 fogs or on curves are frequently prevented. 



Explosives find applications in many industries. The farmer 

 uses them in breaking bowlders, grubbing stumps and felling trees, 

 in shaking the soil to fit it for deep-soil cultivation, and, in the 



wino-growing districts, to 

 free it from phylloxera, 

 while the farmer's friend 

 has tried by this means, in 

 times of drought, to shake 

 the nerves of Jove and to 

 divert the hailstorm from 

 its course. 



The iron founder uses 

 thom in breaking up large 

 castings. The iron smel- 

 ter employs them to clear 

 out obstructions in blast 

 furnaces while the latter 

 are still in operation, the 

 dynamite, protected by a clay envelope, being inserted in the red- 

 hot mass which clogs the furnace. The author has proposed to 

 use the detonating explosives for testing the integrity of large 

 masses of metals and their resistance to shock. 



Dynamite has been employed in fishing, since submarine explo- 

 sions of it will kill or stun fish for a long distance about the charge. 

 This method of fishing, which threatened to deplete the waters, 

 has very properly been ])rohil)ited by law, but guns are employed 

 for projecting harpoons in the whale fishery, and have reduced 

 very much the danger attending this extra-hazardous occupation. 

 Nitroglycerin, inclosed in tin cans three to five inches in diam- 

 eter and five to twenty-five feet in length, is used for shooting oil 

 wells to free them from the solid paraffins with which they l)ecome 

 choked, or to shake the oil-bearing sandstone so as to ]ii<»(liice a 

 greater yield. In this work the loaded can, having a detonating cap 

 attaehed to its top, is lowered by a wire to the bottom of the well. 



Sakk perforated bv Hollow Dynamite 

 Cartridge. 



