435 
Colloidal substances. 
Gelatin */,°/, sol. : + Pig Mxtr squassiga »* /jgis pe ane 
Tragacanth (very dil.): + ‘/,, Glucocholz. natr. '/,,,, + °°/,, 
Traganth (dil. sol.) : + a (P Albumin ov. siee. ve a Piss 
Amyl. oryzae '/, °/,: ep, N „ dialysed + */,, 
Dextrin */,°/,: dT 
Gummi arabic */,,, : of. 497 
Eel (Tauri */73,;:: pete Pe fing 
It goes without saying that with stronger concentrations the 
deflection diminishes in consequence of an increased viscosity. 
As said, the influence of the temperature on waterfall-electricity 
is great. 
Tapwater of 8°: 40 
us rd > LOO: 
Rise of temperature, therefore, increases the positive charge of 
water exceedingly. 
The influence of addition of a saltsolution is also a fact that 
cannot be denied. Alcohol, which, without salt, inereases the posi- 
tive Charge in water considerably, partly loses (his faculty at first 
in the presence of common salt, and even loses it altogether with 
a concentrated salt-solution. Then the negative charge of the salt 
predominates. Salt added to the negatively electrifying camphor 
heightens this negative charge. Camphor and salt co-operate. It 
should seem then that in the case of waterfall-electricity a simple 
summation takes place of the effects of water, salt and the volatile 
addition *). 
In endeavouring to account for these phenomena we might look 
upon spray-electricity as well as upon waterfall-electricity as a form 
of frictional electricity. In either case the friction, between the liquid and 
the air in the outflow of the spray, between liquid and zine plate in the 
waterfall, would set free electrons that are scattered about in the surround- 
ing air. But then the liquid were invariably to be charged positively, 
which turns out differently in a majority of cases, as shown by the experi- 
ments. We presume, therefore, that a more intricate process is at 
work, in which larger corpuscles arise as carriers of the electric 
charge. Such formations might perhaps arise from the so-called ions, 
an equal number ®) of positively- and negatively-charged ions, round 
') In the case of spray- electricity the process is a much more complicate one. 
(See E. L. Backman, Researches Physiol. Lab. Utrecht (5) XIX p. 210. 
*) H. ZWAARDEMAKER. “Le phénomène de la charge des brouillards de substances 
odorantes. Arch. Neerl. Physiol. de l'homme et des animaux’ Tome I 1917 p. 347. 
