Sep"a*ra*ble*ness

from The Collaborative International Dictionary of English v.0.48

Separable \Sep"a*ra*ble\, a. [L. separabilis: cf. F.
   s['e]parable.]
   Capable of being separated, disjoined, disunited, or divided;
   as, the separable parts of plants; qualities not separable
   from the substance in which they exist. --
   {Sep"a*ra*ble*ness}, n. -- {Sep"a*ra*bly}, adv.
   [1913 Webster]

         Trials permit me not to doubt of the separableness of a
         yellow tincture from gold.               --Boyle.
   [1913 Webster]