August 23, 1907] 



SCIENCE 



257 



A NEW RHYTHM AND TIME DEVICE 



After having tried various rotation devices 

 for the production of a series of uniform 

 stimulations at regular intervals, I have con- 

 cluded that the construction of such a ma- 

 chine which will be really reliable, is possible, 

 but would be too expensive to be justified by 

 present needs. Whether the machine could he 

 designed so that gradations through all rates, 

 from say one tenth second to two seconds, 

 would be possible, is a question. Some of the 

 machines which have been used for rhythm 

 work have a fair adjustment for rate, but are 

 irregular in speed, and depend on forms of 

 electric contact which give exceedingly vari- 

 able current strengths. A reliable and con- 

 venient mechanism as yet is not obtainable. 



Feeling that rotation devices are out of the 

 question for accurate work, I have turned my 

 attention to the employment of the dropping 

 of water, varying the rate of fall by changing 

 the level of the water in the vessel from which 



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the drops issue. I have tried several arrange- 

 ments of apparatus for the purpose, and have 

 finally settled on one which is highly satis- 

 factory. Reference to the figure will show the 

 details of this, although not the proportions, 

 as I have not had the parts drawn to any 

 scale. 



About four feet above the sink J?, is a 

 glass jar T, supported on a bracket B. From 



the orifice A at the bottom of the jar, a 

 rubber tube N runs to another jar V, sup- 

 ported by the stage R of the statif (7, which 

 stands on a high table beside the sink. A 

 rubber tube S conducts a small stream of 

 water from a faucet to the jar V, the tube 

 dipping into the water in the jar to prevent 

 disturbance of the surface. The overflow 

 from V is caught by the saucer F in which V 

 is set, and is conducted noiselessly to the sink 

 by the rubber tube W. A band of cloth E, its 

 edge flush with the edge of V, facilitates the 

 overflowing, and keeps the water level con- 

 stant. The siphon GD, of small bore tubing, 

 slightly constricted in one place to retard the 

 flow, and firmly held by a support not shown, 

 drops the water upon a resonator or key 

 placed in the sink. By turning the head P 

 of the screw of the statif, the stage B and 

 jar V may be raised or lowered, thus raising 

 or lowering the water level in T, and acceler- 

 ating or retarding the rate of the drops. 



For auditory stimulation a tin resonator 

 placed in the sink gives admirable results. 

 For other purposes, where it is desired to 

 utilize the making or breaking of an electric 

 current, I have modified a light make-and- 

 break key, by extending the lever and giving 

 it a small disc to be struck by the falling 

 drop. With this, I am able to operate tele- 

 graph sounders or telephone receivers for audi- 

 tory stimulation, and sparks or Geissler tubes 

 for visual, or to record on a kymograph drum. 



Some care is needed in setting up and 

 operating the apparatus. Air bubbles must be 

 removed, although the double jar system re- 

 duces that trouble to a minimum. Shaking 

 of the apparatus disturbs the drops, so ac- 

 curacy will not be attained if the building is 

 subject to much jarring. If the size of the 

 drop is not sufficiently large, a ring of rubber 

 tubing slipped over the end of the siphon D, 

 will increase the adhering surface. The 

 faucet should be adjusted so that a little 

 water is constantly fiowing down the side of 

 V. The orifices K and A, and the tube N 

 must be large enough so that the water level 

 in T is quickly readjusted when the height of 

 V is changed. The siphon GD may be of 



