MR. C. A. BELL ON THE SYMPATHETIC VIBRATIONS OF JETS. 
407 
but is insulated from it by the ebonite. After it lias been fitted on, the top of the 
ebonite plug is turned off so as to present a smooth continuous surface, slightly 
convex. Fine platinum wires welded to E and E', serve to connect them with the 
terminals of the circuit. 
The plug, P, is fitted into a small ebonite cup, C, by which it is supported, and 
into which the jet liquid flows; the liquid is thence carried off by the tube, T, to a 
vessel in which it collects and from which it may be returned to the supply reservoir. 
The cup, C, may be supported on any kind of adjustable stand. 
An indispensable adjunct to any apparatus for experimenting with small jets is 
the filter, F. This may consist of an ebonite cylinder, of about the size shown, 
closed above and below 7 by the screw caps, K and K'. Through the upper cap pass 
two tubes, X and Y. The tube Y (from the bottom of the filter) is connected to 
the jet tube by a piece of black india-rubber tubing, and the tube X, is similarly 
