^ Vol. XXXVIL. Art. 1. K. Fuji. 



firmly against the dram and also jjy a thin j)i('cu ut hanihoo which 

 presses the two overlapping ends of tlie film. When the stand 

 supporting the drum is pulled, tlie axis of the <h-uni is disconnected 

 from its driving shaft by means of a special contrivance (Plate I\^, 

 Fig. 1, a), and the drum with its stand may he taken out of the 

 camera, the operation l)eing accomplished in tlie dark williout 

 any trouble. 



On the shaft of this registering a})paratas. there are two 

 break-circuit contrivances like that of a chronometer (Plate IV., 

 Fig. 1, ^1 b>] Fig. 2), one for the chronograph by whicli tiie number 

 of revolutions of the drum is measured, and tlie other for the 

 shutter described below. 



A kymograph K made by Zimmermann, witli accom|)anying 

 time-markers, was used as the chronograph, the record being 

 oljtained on smoked paper. When the speed of tlie rotation of 

 this instrument is increased to its maximum, the number of 

 revolutions of the registering drum may be accurately determined 

 to three figures. 



The organ-preparation was supported between two zinc plates 

 that served as electrodes. To secure a good contact, and also to 

 avoid the effect of polarisation, if such existed, the surfaces of the 

 zinc plates were covered with kaolin paste, soaked with a saturated 

 solution of zinc sulphate, and then with a layer of the same 

 material kneaded with a jihysiological solution of natrium 

 chloride. 



Since it is found that the form of the discharge curve is much 

 affected by the cliange of temperature, the oigan is ])ut into an 

 electrically regulated thermostat. As the favourable range of 

 temperature for our investigation was found to be <S C. — 15°C. . and 

 because in the warm season this range of temperature is lower than 

 that of the room, the thermostat must be so designed as to ensure 

 that a constant temperature lowa-r than the surrounding temperature 

 be maintained. For this purpose the author constructed a s])ecial 

 thermostat shown in Fig. 1. The moist chamber, in which the 

 organ supported by the zinc electrodes is put, is surrounded by a 

 jacket of transformer oil. in which a toluene I'egulator and • an 



