Photographic recording of ballistic and other rapid phenomena with the aid of the quenched spark
- Publisher
- Elsevier Science
- Year
- 1913
- Tongue
- English
- Weight
- 68 KB
- Volume
- 175
- Category
- Article
- ISSN
- 0016-0032
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✦ Synopsis
Photographic Recording of Ballistic and other Rapid Phenomena with the Aid of the Quenched Spark. C. CRANZ and ]3.
GLATZEL. (De~tsch. Phys. Gesell., xiv, IO, 525.)--After a brief review of the methods used earlier for recording photographically rapidly-occurring processes, such as ballistic phenomena, the authors describe their method, which enables a regular succession of pictures to be taken of a single bullet fired from a pistol, on a falling photographic plate. A direct current quenched gap (of the Scheller type using alcohol) is used, connected to 7oo-volt mains. The capacity in the gap circuit is made up of mica condensers variable from 25,ooo to 6oo,ooo centimetres ; the inductance is kept very low. This inductance and that of the secondary (equal to 18oo centimetres) are in the form of flat spirals so as to secure very close coupling. In the secondary is a small spark-gap (used to illuminate the object to be photographed) shunted by a condenser. The exposures are made on a film which runs over two drums of 89 centimetres circumference, capable of making 9ooo revolutions per second. It is found that the number of sparks passing can be adjusted accurately to any number between 2oo and ioo,ooo per second by (I) altering the capacity in the primary circuit; (2) regulating the intensity of the current in the primary. Reproduced photographs show the method's capabilities. With 64oo sparks per second, the firing of a shot at a piece of wood is seen in all its phases. With io,ooo sparks per second, the movements of the cartridge in the operation of an automatic pistol can be followed. Other records show the bullet issuing from the muzzle, and the accompanying phenomena, taken with spark frequencies of 56,2oo,