249 



§ 7. Taking inlo consideration all the circumstances 



which have an influence on the drawn water quantities we 



shall find 



m = f (r I cl i B). 



When w signifies the water quantity drawn up, r 

 the distance between the point and the meniscus, I the 

 length and d the diameter of the tube, i the intensity of 

 the current, B the resistance of the circuit. 



That the drawn water quantity is proportional to the 

 intensity i of the current results clearly from the curves 

 pl. I— VI and as i is in inverse ratio of the square of the 

 distance, the introduction of these quantities can be regar- 

 ded as determined. The formula is thus 



m = k^f{ld B). 



The way in which m depends of I d and B must be 

 reserved for future investigations. 



The results hitherto produced can be summed up as 

 follows. 



1:0. An electrical current, produced hy an influence- 

 machine, betiveen a cap. tube, standing in ivater cmiduc- 

 ted to the earth, and a j^oint in the air ahove the tube, 

 effects the draiving up of ivater, so that dröps are forr}ied 

 here and ihere in the tube. 



2:o. The electrical current must be directed from the 

 ivater through the cap. tube to the point, wherefor the 

 positive pole of the machine must be united with the earth, 

 the negative pole, with the point. 



3:o. This effect in the form of dröps in the cap. tube 

 can still be observed when the point is at a distance of 

 75 cm from the water-surface ; but the drawing up of wa- 

 ter, without forming dröps, is going at a much greater 

 distance. 



4:o. The intensity of the current can be determined 

 by the number of sparks betweens the spheres of a spark- 

 micrometer in connexion with a leyden jar of known capa- 



