FIG. 29.
TORPEDO BADLY FIRED.TORPEDO PROPERLY FIRED.
The great value of chronophotography is unquestionable for use in every case where the body whose rapid changes of position or form we wish to know is inaccessible to us, or its movements cannot be mechanically traced.
Chronophotography has been used in France for studies touching the military art, being employed for registering the firing of projectiles having a relatively slow motion, such as the explosion of stationary torpedoes, the recoil of guns, the motion of automobile torpedoes, etc. Special arrangements are provided to permit of electrically controlling the phenomenon to be photographed. The apparatus is described in detail in the “Scientific American Supplement,” No. 743.
We present a [diagram] showing the results obtained by photographing the firing of torpedoes. Although the velocity of these projectiles is not very great, about sixty feet per second, it is yet very difficult for the eye to take exact account of what is occurring during the launching. As the net cost of a torpedo is considerable, it is essential that the conditions which influence the regularity of its submarine flight shall be known with precision. If it inclines in front more or less in plunging, the regularity of its running will be put to hazard; if, on the contrary, it falls flat upon the water, the results will be very different. Our engraving shows the torpedo starting from the tube and traversing the different panels in the field of firing. In the first half the torpedo, gradually inclining, falls point foremost; it has been badly fired. In the second series, on the contrary, the torpedo is maintaining itself horizontally, and, in a manner, moving always parallel with itself. Under such circumstances it falls flat and starts off normally and regularly to the object to be reached. This shows the great utility of chronophotography.