The Davis flue brush patent, No. 181,416, is made by sticking the wire splints through holes in an iron cylinder, there being no wood about its construction.
Several cases had been tried in other States involving the validity of the Wright patent, which had resulted in Mr. McArthur's favor, but after exhaustive argument in the case at Pittsburg, Pa., the court held the Davis brush not to be an infringement on the Wright patent.
How Long Should a Nervous Patient be Treated?
The question of how long treatment should be continued in a neurotic case when no evident benefit is produced has recently been raised in a Hamburg law court. A medical man, says the Lancet, having as a patient a merchant suffering from "nervousness," treated him by galvanism. Altogether he galvanized him 445 times, but the nervousness did not disappear. Then came the matter of fees. The sum claimed was $556. The merchant disputed this on the ground that the treatment ought not have been continued so long, as it was not producing any benefit. The court referred the matter to the medical board, which gave as its opinion that the doctor ought to have asked the patient, after some fifty sittings, whether he would like to continue them, as it was doubtful whether the treatment was doing any good. The court, however, declined to accept this view, holding that it was for the patient to say when he had tried the treatment as long as he was disposed to pay for it, and so gave judgment for the full amount claimed. This judgment seems to accord with the principle that applies to newspaper subscriptions. A man must pay for his paper as long as he takes it from the post office.
TORPEDO BOAT ARMED WITH PNEUMATIC DYNAMITE GUNS.
In former issues of the Scientific American we have given illustrations and detailed descriptions of the pneumatic dynamite gun invented by Lieutenant E. L. Zalinski, of the U. S. Artillery Corps. This gun, it will be remembered, was designed to throw a projectile loaded with dynamite or nitro-glycerine by means of compressed air; and so successful were the experiments carried on with it at Fort Lafayette, under the supervision of a board of naval experts, that Congress eventually appropriated $350,000 for building a swift torpedo boat, large enough to go to sea, and to be armed with three of these guns. Contracts for this boat have been signed with the Cramps.
The upper view in the accompanying engraving is a longitudinal vertical section, the lower one being a plan view. The following details regarding the boat we take from the Sun. The boat will be 250 ft. long, 26 ft. beam, and will draw 8 ft. of water. Her displacement will be about 800 tons. The engines will be of the triple expansion type, of the best known design, and the guaranteed power will be 3,200. She will be propelled by twin screws, and it is expected that the guaranteed speed of 20 knots an hour will be exceeded.
The three dynamite guns are to be placed side by side, at the elevation indicated in the upper view. They are to be fired in their places, but their range can be varied by increasing or diminishing the charge of air let in behind the projectile. An extreme range of one mile is put down in the contract, and the weight of gelatine to be thrown is 200 pounds; but the guns, as now building, will throw 400 pounds instead of 200 pounds, and the effective range will probably be about two miles. Air chambers and compressors of sufficient size and power are provided to enable fifteen shots to be fired to the distance of one mile without stopping; but if the boat were heading for the enemy at full speed, thirty shells could be thrown before the air would be exhausted and the cruiser obliged to turn tail. Thirty shells would mean the explosion of 12,000 pounds of nitro-glycerine about the enemy.