Bubble Recorder for Mariotte Bottles.

Abstract

The recording of bubbles passing through a Mariotte bottle by means of a tambour offers considerable technical difficulties, as for instance, in the lung perfusion, described by Sollmann and von Oettingen; 1 nor does the device, worked out by Atzler and Frank 2 give satisfactory records.

Very good results have been obtained with the following device which utilizes the oscillation of the fluid in the inlet tube of the Mariotte stopper to close a circuit between 2, pair of wire electrodes adjusted in the lower end of the tube. The electrodes consist of copper wires fused into narrow glass-tubes for insulation, with projecting platinum tips. One wire is adjusted to about one millimeter above the lower rim of the tube, the other wire dips about 0.5 cm. into the fluid. The 2 electrodes are held together by a rubber-ring through which a pin passes, which rests upon the upper rim of the Mariotte tube (Fig. A). By shifting this ring up and down, the electrodes can be adjusted to different levels; they are connected with a current of no volts and with a relay arrangement, the dry cells of which feed a signal magnet, as described by Biskind and Dan. 3

When the fluid within the Mariotte tube rises a little after each bubble, the 2 electrodes are short-circuited, and a signal mark is produced on a moving drum. There is virtually no danger of changing the composition of the saline solution by electrolytic decomposition products, because the contact between saline and electrodes is short, and the quantity of saline coming in contact is very small.