MORSE. 



EVAPORATION FROM THE SURFACE OF A SPHERE. 



365 



It was therefore expected that any influence of the size of the particle 

 of iodine on the rate of evaporation would only appear for very small 



spheres indeed and that for all particles of sensible dimensions the rate 

 would be proportional to the surface, so that 



dm _ h 

 ~~ ^ — fcs ', 

 dt ' 



or since the change in mass is being followed 



