Sub ma-rine′ Pho-tog′ra-phy.
A photographic apparatus by
Dr. Neumayer of
Berlin, for ascertaining the temperature and direction of deepsea currents.
[
2440]
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Storm's submarine explorer. |
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Submarine guns. |
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American submarine gun. |
It consists of a copper case hermetically closed, and furnished with an exterior appendage resembling a rudder.
Within this case a thermometer and compass are inclosed, each in a glass vessel containing traces of nitrogen-gas.
The apparatus is completed by a small electric battery.
When this apparatus, attached to a sounding-line, is caused to descend into the sea, the action of the current upon the rudder determines the position which it assumes.
The direction of the current is thus indicated by the relative position of the needle and the rudder, while the temperature of the vicinity is shown by the thermometer.
But in order that these indications may be read at any desired spot in the ocean depths, it is necessary to fix them at the moment required.
A leaf of photographic paper is placed in a proper position next to the glass vessel containing the instruments.
When it is desired to obtain the reading of the instruments, an electric current is sent through the nitrogen gas contained in these vessels.
This produces a very intense violet light capable of acting chemically upon the photographic paper for a time sufficiently long to reproduce the shadows of the needle and of the column of mercury.
At the end of three minutes, it is claimed, the operation is finished, the apparatus may be brought to the surface, and the paper, being removed from it, presents a record of the conditions observed in depth.