Читать книгу The Complete English Wing Shot онлайн

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We are still in the dark ages of “pressure” testing, or trying the strength of powders by the work they do upon plugs inserted through the walls of testing guns, and, outside, in contact with lead or other metal that the explosion, in moving the plugs, crushes. In doing this the powder-gas does “work” which would be correctly measurable in foot-tons, but is supposed to be measured in static pounds, which is similar to dropping a weight upon a scale balance and mistaking the weight for the work done by the drop. For instance, if we drop a pound weight a foot on to a scale balance, the work it does is equal to one foot-pound. But if we place it on the scale gently, it will just balance one pound on the other side. One is weight and the other is energy, which are not comparative terms. Yet in testing powders the fashion is to take the measure of some unknown proportion of the energy and to call it static pounds.

On the other hand, the fashion is to make the exactly contrary mistake in testing guns for shooting strength. The flattening of the shot pellets on a steel plate is the result of energy; here the flattening of lead by which “pressures” are erroneously taken is ignored and scouted, and velocity is considered the thing to judge by, although it is only the velocity of one pellet out of three hundred which, at 20 yards, vary by as much as 300 foot-seconds mean velocity.