344 Lord Kelvin and Messrs. Maclean and Gait. [Feb. 21, 



in the insulated jar, showed, when air was bubbled through it for ten 

 minutes, a negative electrification of f- volt. 



'22. Ten drops of paraffin oil added to water reduced the electri- 

 fication to about half of that obtained from water only. Thirty drops 

 reduced it to about a tenth, which as it amounted to only 0'4 volt 

 during the time of the experiment is negligible. 



23. Ten drops of benzene reduced the electrification to half, and 

 thirty drops to about a third of that taken by pure water. 



24. A saturated solution of granulated phenol (carbolic acid) 

 was made, and small portions of it added to the water in the jar. 

 Several experiments showed no diminution in the electrification as 

 long as the quantity of the phenol solution present in 'the water was 

 under 10 per cent. With 25 per cent, the electrification was reduced 

 to a third. With strengths greater than this up to saturation the 

 electrification was reduced to one-sixth. 



25. A saturated solution of common salt was prepared. Blowing 

 air through 200 c.c. of water containing the quantities of the salt 

 solution mentioned, gave us in 10 minutes the following electrifi- 

 cations : 



(a.) '004 per cent, of saturated solution of salt in water. . 2 '4 volts positive. 

 J. 0'02 , . . 1 -2 



(.) 0-1 



WO -5 

 (e. 2-0 



0-6 

 0-4 

 0-15 

 O'O 



26. Several experiments showed that with 200 c.c. of water con- 

 taining not more than ten drops of absolute alcohol, practically the 

 same amount of positive electrification (4 volts in ten minutes) is 

 obtained as if pure water were used. With fifty drops less than 

 2 volts were got, and with 100 drops less than 1 volt. 25 and 50 

 per cent, alcohol in the water gave very small and hence negligible 

 positive electrification. 



27. One drop of saturated solution of copper sulphate in 200 c.c. 

 of water showed 1 volt positive in 10 minutes. With -| per cent, of 

 it in the water, the electrification was reduced to a fraction of a 

 volt positive. With greater proportions of copper sulphate present, 

 up to saturation, slightly negative electrifications were obtained, but 

 never amounting to more than about one-tenth of a volt, and hence 

 negligible. 



28. On blowing carbonic acid gas, from a cylinder obtained from 

 the Scotch and Irish Oxygen Company, through pure water in the 

 glass jar, the water became electrified to 8J volts positive in ten 

 minutes. Blowing the breath through water gave an electrification 

 of 3 volts positive in the same time : this diminished result is doubt- 

 less due chiefly to the diminished rate of bubbling. 



