1275 



a colloidal system, consistinj^ of the phase liquid (dispers) and gas 

 (dispei'gent). On the surface of the droplets there is an electric 

 poten Hal, on the bigger droplets by which the charge on the screen 

 is measured, it is negative. Of the other salicylic acid salts we had 

 still at our disposal strontium- and bismuth-salt. They also possess 

 a moderate electiifying power, just as sodiumbenzoate. 



The esters of salicylic acid at our disposal: aspirin, novaspirin, 

 diaspirin, the methylsaUcylate and the spirosal, all yielded powerful 

 charges. 



Group c. The third group comprises thiee series: u thechinolin- 

 derivatives, /^ the pyi-azols, y the paramidophenols. There is only 

 one insoluble substance amongst them, all the rest are soluble and 

 moreover crystalline. 



For cilrophen the lowering of the surface-tension could not be 

 demonstrated. We also found that with most of the substances the 

 surface-activitj' was inconsiderable. Only with enphorin, acetopyrin 

 and kairin the loweriug may be called significant. vSiight volatility 

 is generally noticeable if the evaporation area be large. 



As regards the intensity of the electrical phenomenon it may be 

 observed that the completely insoluble representative of grou[) c 

 does not yield a charge, which is in keeping with its insolubility; 

 that the phenomeuon occurs with moderate intensity in the case 

 of pyramidon, phenacetin, and cilrophen ; that it is somewhat 

 stronger with kairin, but extremely distinct with antipyrin, salipyrin, 

 acetopyrin, tussol, antifebrin, and euphorin. 



From the foregoing we may therefore conclude that all anti- 

 pyretica, except those that are completely insoluble, yiehl the elec- 

 trical phenomenon. 



As has been set forth in previous publications, the electrical charge 

 of a nebula is carried exclusively in the droplets it holds. Being 

 sprayed under an overpressure of two atmospheres the tluid emerges 

 froni the nozzle of the sprayer in the shape of little diops. Of these 

 drops the smaller ones are blown about and scattered in all direc- 

 tions. For odorous substances they are charged negatively. The bigger 

 drops, which are charged positively, rush ahead in straight, diver- 

 gent lines. When caught up at a [)roper distance, (for the antipy- 

 retica at 25 cm. from the sprayer) on an insulated screen, the latter 

 will receive a |)ositive charge that is pretty strong, thougli it is never 

 so strong with aulipyretica as with odorous substances (in aqueous 

 solution). 



