Surron—Study of Evaporation from Water-Surfaces. 175 
time the electrified water was decidedly lighter. . . . This 
experiment shows that the disturbing influence which assists 
evaporation is peculiar to the negative pole even at atmospheric 
pressures.” 
Rowell, in his chapter on “‘ Hvaporation,” apparently accepting 
Nollet’s results, says :—‘‘ In accordance withthe proposed theory 
I was led to think that evaporation would not go on so freely from 
an insulated vessel as from an uninsulated one, and, in 1841, I 
tried several experiments, the following account of which appeared 
in the Phil. Mag., Jan., 1842 :—‘ In a warm room, over an oven 
in daily use, I suspended with silk threads two shallow vessels, 
eight inches and a half in diameter, containing eight ounces of 
water each ; a small copper wire was hung from one vessel to the 
earth to take off the insulation, both vessels being similarly 
suspended in every other respect; after being suspended for 
twenty-five hours, the insulated vessel had lost two ounces, eleven 
dwts., and fifteen grains; and the other vessel three ounces, six 
dwts., showing an excess of evaporation from the non-insulated 
vessel of {fourteen dwts., nine grains. JI have tried similar 
experiments with water placed in the rays of the sun, and on 
all occasions the evaporation has been greatest from the non-insu- 
lated vessel... And in the Annals of Electricity, vol. viii., p. 825, 
Mr. T. Spencer, in an article on Atmospheric Electricity, after 
referring to the foregoing experiment, says:—‘I have repeated 
a similar set of experiments, and with nearly similar results; 
always, at least, showing an excess in favour of the non-insulated 
vessels of water.’ Thus the agency of electricity in evaporation 
is shown in varlous ways ; as electricity goes off during evaporation, 
an excess of it accelerates evaporation, and, as in the last experi- 
ments, the want of it retards evaporation.” 
Whether the surrounding conditions were such as to justify 
Rowell’s deductions is more than I know, although he seems to 
have got the same effect indoors and out. At any rate, I have 
not succeeded in getting it. During the dry, clear Kimberley 
winter of 1904, for about three months, I exposed four almost 
1 “On Electrical Evaporation,’’ Proc. Roy. Soc., 1891, No. 302, p. 88. 
2 G. A. Rowell, Hon. Memb. Ashmolean Soc., An Essay on the Cause of Rain, &., 
1859, p. 41. 
