256 Journal of Experiments, Nov. 1772 



such manner as that a slight shock should be felt in [the] elbows : it was then 

 made to pass through rain water in a tube of a rather greater capacity, and the 

 electricity made rather stronger. The wires were obliged to be placed within 

 18 of each other in order to feel the shock in the same degree. Therefore the 

 electricity meets with more than 230 times the resistance in passing through 

 rain water than salt. 



The above jars were electrified till light paper cylinders began to separate, 

 and the shock made to pass through a tube filled with rain water. The wires 

 were obliged to be brought within -48 inches of each other in order that the 

 shock should be just felt in the elbows. 



When the same tube was filled with saturated solution of sea salt diluted 

 with 29 its bulk of rain water, a much greater shock was felt when the wires 

 were at i6J inches from each other. 



Therefore electricity meets with much more than 34 times the resistance 

 from rain water than from a saturated solution of sea salt with 29 of rain water. 



When the same tube was filled with kitchen salt in 1000 of rain water, the 

 wires must be brought within 4-4 inches; with pump water within 2 inches, 

 and with spirit of wine almost close ; therefore the resistance of 



Pump water } . (4! 



., . ... } is < " less than that ot ram water. 



S. salt in 1000 of ram water) [9 



Mon. Nov. 16 [1772] with straw electrometer. With sea water a shock was 

 felt when the wires were igj inches distant; with rain water when they were 

 at about -19 inches distant. Therefore resistance of sea water is about 100 

 times less than that of rain water. 



G 

 A 



525] Exper. Whether force with which two bodies repel is as square of re- 

 dundant fluid in them*. 



Tried by pith balls hung by threads. 



A and B are the coated plates A and B, the bottoms of which communicate 

 with the ground, D and d are two bits of wood resting on them, supporting the 

 pith balls E and e. G is a bit of wood for making a communication between 

 them. The wire for electrifying the plates rests on B, and is so contrived that 

 when that is lifted up the wood G is let fall on the plates. 



The pith balls E had bits of wire made to run into them in order to increase 

 their weight. 



A paper with divisions was placed 6 inches behind the pith balls and a 

 guide for the eye 30 inches before them. 



* [Arts. 386, 563, 567.] 



