between Electrostatic Tubes and Insulator 



135 



of the tubes. Such pressures should be experienced by the 

 walls o£ vessels containing electrolytes. To confirm the ex- 

 periment and to be assured that the movements are not 

 due to currents of liquid, two electrolytes were placed in 

 series, both consisting of distilled water. After the mica had 

 moved in one, a small quantity of chloride of sodium was 

 dissolved in it. The current became stronger, but the electro- 

 static field became weaker and the mica showed hardly any 

 trace of movement. Tinfoil floating in the water and replac- 

 ing the mica behaved in the opposite way. The author 

 intends to make the third experiment in rarefied gases, where 

 by ionization the electrostatic tubes may also coincide with 

 the tubes of current, but where the influence of the statical 

 lines upon the walls will also come into account. 



Fourth Experiment. — A mica pendulum (fig. 5) movable 

 round a light axis of glass is placed between the termiuals of a 

 Holtz machine with the axis parallel to the line joining the 



Fk\ 6. 



0* K 



terminals. If this line passes through the plate and the 

 spark is obliged to turn from the most direct route, the 

 pendulum retreats from the terminals. If the air is ionized 

 by the discharges the effect may be attributed to the reactions 

 of the electrostatic tubes on the edge of the mica, but if not, 

 we cannot so explain the motion. The two faces of the 

 mica may perhaps be electrified by charges of the same sign 

 respectively as those in the points A and B, and the emplace- 

 ment to the right may ba due to repulsion of like charges. 

 It would be necessary to put a flame under the points and 



