The Collaborative International Dictionary of English v.0.48:

Insphere \In*sphere"\, v. t. [imp. & p. p. Insphered; p. pr. &
   vb. n. Insphering.] [Cf. Ensphere.]
   To place in, or as in, an orb a sphere. Cf. Ensphere.
   [1913 Webster]

         Bright a["e]rial spirits live insphered
         In regions mild of calm and serene air.  --Milton.
   [1913 Webster]