432 M. W. Hoitz on a new Electrical Machine. 



constantly with a feeble bluish light. Stratification is obtained 

 when a and c are simultaneously connected with a larger jar. It 

 is also obtained if the electrodes are pointed and at a very small 

 distance. With a greater striking-distance, and especially with 

 the use of the above-mentioned small jar, the tube is so in- 

 tensely luminous that the phenomenon is quite visible even by 

 broad daylight. 



Physiological actions only occur if there is at the same time a 

 layer of air in the circuit. If the current of sparks is taken 

 directly on the hand, it produces an extremely smart pricking 

 sensation. If the human body be interposed between b and c, 

 distinct shocks are felt even without a jar. But if a and c are 

 simultaneously in connexion with the small jar, if the electrodes 

 are points and so near that they all but touch, the sensation 

 of a tolerably powerful induction-apparatus is felt. By gradually 

 increasing the striking-distance, this action may be increased to 

 any extent; but at a distance of o 1 ^", where there are still 

 more than fifty discharges in a second, it is unendurable. 



To exhibit the heating effect which the current produces in a 

 thin wire, I interposed a Riess's air-thermometer in the circuit. 

 With a slight inclination of the instrument the liquid flowed out 

 of the tube ; with a greater inclination it assumed a more or less 

 constant position. To test the heat of the sparks, I allowed 

 them to strike through a narrow glass tube into which the elec- 

 trodes were led. Within a short time it was so warm that I 

 could light a match at it. A direct lighting by the current w T as 

 produced by giving the electrodes the form of points and bring- 

 ing them as near as possible. Phosphorus and gun-cotton were 

 immediately inflamed between such points, and finely-divided 

 charcoal became incandescent. Tinder was only ignited with 

 great difficulty, and gunpowder not at all. 



Of chemical actions, the decomposition of water may be 

 mentioned ; but I may remark that I have only succeeded in it 

 with wires melted into glass tubes. The little bubbles ascend 

 in fine but continuous streams, and at one electrode apparently 

 in double the quantity at the other. By interposing a layer of 

 air, this action was only enfeebled. 



To confirm the magnetic actions, I used the extra coil of a 

 Stohrer's induction-apparatus. In the inside, near the open 

 end, a magnetic needle was placed, and the current led continu- 

 ously through the spiral; I obtained thus a pretty constant 

 deflection of 35° to 40°. 



Prom further experiments it will be seen to what degree these 

 actions can be increased. In order to ascertain the influence of 

 the magnitude of the disk, I am having machines made of 

 various sizes, and hope soon to be in a position to report on 



