Considerable stress has been laid on the fact that in this experiment the charge was in actual contact, and yet did not effect complete penetration. It is even gravely asserted that an actual torpedo would have rebounded a certain distance before explosion took place, and this would diminish its effect. In the first place, the detonation of guncotton is practically instantaneous, so that impact and explosion would be simultaneous. We are hardly prepared to allow an inch rebound, but will concede that until actual proof convicts us of error. In the second place, it is possible that a distance of three or four feet between charge and ship would rather augment than diminish the effect produced in the case of such an explosive as guncotton when sufficiently immersed. It is possible the intervening water thrown against the side of the ship would do more damage than the gas liberated in actual contact. At any rate, experiments some years ago with smaller quantities of both dynamite and guncotton showed that when exploded 4 ft. from the bottom of a ship, enormous damage was inflicted on her.
Although it is generally estimated that guncotton is about four times more powerful than gunpowder, this does not appear to hold good under all conditions; while, on the other hand, for certain purposes, ten times the amount of gunpowder would not produce the same result. This is proved by the ease with which the strongest chain cable and wire rope can be ruptured by a small charge of guncotton, which even more than ten times the amount of gunpowder could not accomplish. This is due to the peculiar shattering action of detonated guncotton, which the slower burning substances does not possess, its characteristic being more of the nature of a push than a blow. Taking into consideration the method in which the hull of the Resistance had been strengthened for this experiment, and the exact locality chosen for the explosion, it is probable that less than twice the amount of gunpowder would have caused a more complete breach through the coal protection. The torpedo is stated to have had everything in its favor; whereas, in our opinion, all the advantages were on the side of the ship. The attack was made at her strongest point, where the coal was specially disposed, and her shape under water lent no assistance to the explosive. To assume from this that if a similar torpedo struck lower down, or further aft, or against the propeller, the ship would still have "her offensive powers not materially impaired," is to express an opinion with which few will be found to concur.
Under the alternative circumstances mentioned, half the amount of explosive might practically disable the vessel, though her flotation need not be overcome. Whitehead torpedoes need not necessarily be limited to a depth of 10 ft., as by slightly strengthening their construction they could be run 20 ft. below the surface. We presume it will be allowed that this would increase their destructive power, especially in the vicinity of engines and boilers, which now occupy so much space. In a similar manner there is no difficulty in increasing the charge of a locomotive torpedo to a point at which it becomes irresistible, whatever system of internal protection may be devised. This has, in fact, been going on for some time; more than one nation possesses torpedoes armed with 100 lb. of guncotton, and if we do not, it is simply because former experiments led us to believe sufficient damage would be caused by a less quantity. We can only consider that disproved on demonstration by further trials under conditions less favorable to the ship, and we venture to predict some delusions will then be dispelled which this particular experiment seems to have occasioned.
TORPEDO EXPERIMENTS AT PORTSMOUTH—DAMAGE DONE TO THE PORT SIDE OF H.M.S. RESISTANCE.
Steel Wire Brush Patent.
Before Judges McKennan and Acheson of the United States Circuit Court for the Western District of Pennsylvania, at Pittsburg, Pa., No. 16 of November term, 1886, a question arose as to whether a steel wire brush for cleaning castings, and a steel wire brush for cleaning boiler flues, was an infringement on what is generally known as the Wright patent, No. 59,733, and the reissue, No. 2,598, owned by Joseph McArthur, of New York city.
The Wright patent consists of a wooden block with a series of pairs of holes. A bundle of wire splints is doubled and the ends inserted in the holes, being held by the wooden bridge between the holes and by a wooden back screwed to the block.
Joseph H. Davis, of Sewickley, Pa., the defendant, under his casting brush patent, No. 232,600, the construction of which consists in the doubling of the wire splints and inserting in one hole of a wooden block, and fastening by means of weaving a wire through the loop, the wire being held in place by a wooden back fastened on by driving wrought iron nails through the block and back and clinching on the back, thus making the block and back practically inseparable.