Smithsonian Report, 1913. — Devaux. 



Plate 7. 



Film of Oleic Acid upon Mercury. Color, Violet-Rose (140 w?). 



The surface of the mercury had already received a drop of acid wiiich had entirely con- 

 tracted into droplets. The new drop expanded very slowly with clearly defined thick bor- 

 ders. These borders have already been transformed into chaplets of great drops such as 

 are always found about the black spots which appear at various moments in the expansion 

 of a film. 



