The number of elementary precipitable drops depends,not only on the number of activated droplets, but also on the size distributions of those droplets.Calculations

made by Howell and by Neiburgerand Chien show that drops which grow only by condensation develop toward a uniformsize. East hasshown that, if condensation an d coalescence occur simultaneously, development of auniform drop size would not normally be expected.

Ifthedroplet sizes just after condensation tend toward uniformity, the high concentration of droplets will actually break the colloidal stability. Then the concentration of droplets,rather than size of the individual droplets,will be more important in determining the concentration of precipitable drops.