286 yournal of Experiments, Nov. 1773 



It was found that when the straw electrometer separated to i + o, I just 

 felt a shock in my wrists, and when it separated to 2 -f- o, I felt a pretty brisk 

 one in them but not higher up. 



I then gave the shock its choice whether it would pass through my body, 

 or 5-1 inches of a column of a saturated solution of sea salt contained in a glass 

 tube, i inch of which holds 9-12 grains of fresh water, the wires running into 

 the salt water being fastened to brass wires as before. 



I found the shock to be just the same as before, and found too that in- 

 creasing the length of the column of salt water not more than J of an inch made 

 a sensible difference in the strength of the shock. 



Therefore the electricity meets with the same resistance in passing through 



2540 inches of wire whose base is - - = as through 5-1 inches of salt 



78 x 144 79 



water whose base is 9-12. 



Therefore, if the resistance is as the 1-08 power of the velocity, the resistance 

 of iron wire is 607,000 times less than that of a column of salt water of the same 

 diameter*. 



577] Comparison of conducting powers of saturated solution of sea salt and 

 distilled water. 



The shock of i jar charged till the straw electrometer separated to i + o, 



( *8 

 discharged through a column of < inches of a mixture of saturated solution 



t greater 

 of sea salt with 99 of distilled water in tube 6, was -j ? than when it was 



discharged through 35^ inches of saturated solution of sea salt in tube 2. 



By a former experiment, the shock passed through ' > of the mixed water 



was j| r than through 40 J of saturated solution. 



By a mean, the resistance of one inch of the mixed water is equal to that of 

 38 of the saturated solution, therefore allowing for the different bases of the 

 tubes, the resistance of the mixed water is 39 times greater than that of the 

 saturated solution. 



The shock of two jars, charged to 4 + 0, and discharged through ~~ 



( CTf*3.tf*I* 



of distilled water in tube 5, was < ' than when it was discharged through 



23 J of the above-mentioned mixed water in tube 8. 



( *R 

 By a former experiment, the shock passed through | of distilled water 



was |f than through 23 J of the mixed, 



(less 



* [If the resistance is as the velocity, resistance of saturated solution of salt is 

 355.4 times that of iron wire. By Matthiessen and Kohlrausch it should be about 

 502,500. See Note 32.] 



