L. MECHANICS AND ENGINEERING. 483 



NEW COMBINATION OF NITRO-GLYCERINE. 



Nobel, the well-known inventor of nitro-glycerine and of 

 dynamites, has patented a new mixture which is of greater or 

 less power according to the variation of the proportion of 

 the constituents. The strongest mixture consists of 68 parts 

 of nitrate of barytes and 12 parts of some coal rich in hydro- 

 carbons, the whole saturated with 12 parts of nitro-glycerine. 

 Nearly equal to this mixture is one consisting of 70 parts of 

 nitrate of barytes, 10 of resin, and 12 of nitro-glycerine. An 

 addition of 5 to 8 parts of sulphur considerably increases the 

 action of both. The ignition takes place by means of fulmi- 

 nating silver and a fuse. 18 (7, March 9, 1872, 159. 



EXPERIMENTS WITH LITIIOFEACTEUR. 



The explosive called lithofracteur, which has been brought 

 into notice within a comparatively recent period, bids fair to 

 be an extremely valuable addition to the resources of mili- 

 tary and civil engineers a series of experiments, prosecuted 

 under the British government, having been highly satisfac- 

 tory in that respect. This substance is manufactured in Ger- 

 many, and put up in thin, water-proof paper cartridges, about 

 one inch in diameter, and weighing \ an ounce, 1 ounce, 1-J 

 ounces, and 2 ounces. These are packed in a stout card-board 

 box, containing altogether 5 pounds, the box being tied up 

 in a stout paper envelope. Ten of these are then packed in 

 a strong w T ooden case, the lid of which is nailed on with zinc 

 nails, each case thus containing 50 pounds. 



The experiments with this substance were varied, repre- 

 senting almost all the instances in which the application of 

 such an explosive might be made. Among these was one in- 

 tended to show that ordinary percussion did not explode this 

 substance, an important consideration with reference to safety 

 in its transportation. 



In another experiment a double stockade of 9-inch railway 

 sleepers was sunk 18 inches in the ground, with an interval 

 of 7 feet between the rows, each row consisting of 14 sleepers. 

 Against the foot of the front row were laid two thin sheet 

 zinc tubes, containing 150 pounds of the lithofracteur. These 

 were fired by a fuse, and resulted in an explosion audible 14 

 miles away. The stockades wore all torn into match-wood, 



