His results are as follows: 
                                           Pounds. 
  At 5 feet................................ 231/2
   " 10 " ................................ 75
   " 20 " ................................ 177
   " 30 " ................................ 274
   " 40 " ................................ 369

Regarding the comparative effects of gunpowder and the high explosives, I think Gen. Abbot’s estimate of a varying value for powder is more admissible than the fixed value assigned by Col.  Bucknill.  Gunpowder gives a push and detonating compounds a shock; as the quantities increase, the push reaches farther than the shock.  According to Gen. Abbot, 100 pounds of dynamite No. 1 will have a destructive horizontal range of 16.3 feet, while the same amount of gunpowder will only have a range of 3.3 feet.  Five hundred pounds of dynamite, however, will have a horizontal range of 35 feet, and 500 pounds of gunpowder will have 19.5 feet; the ratio has diminished from five to two.  Whether 6,500 pounds or 12,000 pounds per square inch is necessary to crush the bottom of an armorclad will depend largely upon how far apart the frames of the ship are spaced and what other bracing is supplied, as well as many local circumstances.  It is difficult to judge exactly of these matters.  Some four years ago the Italian government adopted treble bottoms for their heaviest ships as a result of experiments with seventy-five pounds of gun-cotton (the charge of an ordinary Whitehead locomotive torpedo) against a caisson which was a fac-simile of a portion of the proposed ships.  Only two of the bottoms were broken through, and when the space between the two inner bottoms was filled with coal, only the outer bottom was broken.  According to the formulae of either Abbot or Bucknill, there should have been a local pressure of at least 300,000 pounds per square inch on the outer skin, and yet judicious interior arrangements rendered it harmless to the target.  It would not, however, be safe to conclude that the torpedo was thus vanquished; the immediate result was simply to create a demand for larger locomotive torpedoes for local application, and but little light was thrown upon the results which might be anticipated from a large mine at a greater distance, whose radius of explosive effect would embrace a larger portion of the ship, and especially if the ship were nearly over the torpedo.  The local effect of a detonation is different from the transmitted shock.  Experiments in England have shown that 500 pounds of gun-cotton at forty feet below any ship will sink her, and at a horizontal distance of 100 feet, damage to the interior pipes and machinery is to be expected.

The fact that the high explosives are so much heavier than gunpowder has an important bearing on the size of the containing case.  Their sp. gr. is as follows: