PRESIDENTIAL ADDRESSES. 555 



the molecular torrent by a neighbouring magnet ; 

 the tremendous heating effect of the torrent from 

 a concave electrode when glass, metal, or any 

 ponderable substance is placed in the focus ; the 

 phosphorescence produced on a plate coated with 

 sensitive paint by a molecular torrent skirting 

 along it ; the brilliant colours turquoise-blue, 

 emerald, orange, ruby-red with which gray 

 colourless objects and clear colourless crystals glow 

 on their struck faces when lying separately or piled 

 up in a heap in the course of a molecular torrent ; 

 " electrical evaporation " of negatively electrified 

 liquids and solids ; l the seemingly red hot glow 

 but with no heat conducted inwards from the 

 surface, of cool solid silver kept negatively electri- 

 fied in a vacuum of - 00 ~ ^ of an atmosphere, 

 and thereby caused to rapidly evaporate. This 

 last-mentioned result is almost more surprising 

 than the phosphorescent glow excited by molecular 

 impacts in bodies not rendered perceptibly phos- 

 phorescent by light. Both phenomena will surely 

 be found very telling in respect to the molecular 

 1 Roy. Soc. Proc., June n, 1891. 



