Physiology. — “On Spray-electricity of Solutions of Electrolytes’. 
By Prof. H. ZWAARDEMAKER and Dr. H. Zrenuisen. 
(Communicated at the meeting of April 23, 1920). 
Our experience regarding Spray-electricity of aqueous solutions 
has led to the following results *) 
| Charge imparted by the nebula per 
cc. of sprayed liquid in 10 10 
| Coulombs. 
Saturated solutions. 
Odorous substances (27 in numb.) onan average 81 (extremes 300 and 1) 
Saponins (22, soluble) lees eee By 9 16 cod iim 
Antipyretics ( 9, soluble) lie ight eeen 15 „ 2w) 
Alkaloids (11, soluble) ay is 2.9 ( ss CRS 
Perfectly pure water does not yield spray-electricity (fresh-distilled 
water); no more does Utrecht tap-water. Since, in subsequent expe- 
riments, with more sensitive apparatus also solutions of electrolytes 
proved to impart a weak charge, which may be positive, as well 
as negative, these solutions were examined more in detail. To this 
we were prompted all the more, since all groups of physiologically 
active substances mentioned above, gave only a positive charge, 
which got weaker with every following dilution, while ultimately 
there was no charge whatever. The strong positive charge of the 
substances is apparently correlated to their volatility, which mani- 
fests itself, as has been described before, in their odour, in the 
odour of the nebula formed in spraying, in the decrease of the 
charge in their solutions, when an air-current is sent through, in 
the camphor-phenomenon, exhibited by many, in their boiling-point, 
etc. In the case of pure odorous substances this correlation controls 
smell-intensity and electrifying power. Generally the substances giving 
a positive charge exert a lowering influence upon the surface tension 
of the boundary surface air-water. 
!) Proceedings 25 March 1916, 27 May 1916, 30 Sept. 1916, 23 Febr. 1918 
Arch. Neerl. de Physiol. t. 1, p. 847, 1917. 
