The Collaborative International Dictionary of English v.0.48:

Immerge \Im*merge"\, v. t. [imp. & p. p. Immerged; p. pr. &
   vb. n. Immerging.] [L. immergere; pref. im- in + mergere to
   dip, plunge: cf. F. immerger. See Merge, and cf.
   Immerse.]
   To plungel into, under, or within anything especially a fuid;
   to dip; to immerse. See Immerse.
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         We took . . . lukewarm water, and in it immerged a
         quantity of the leaves of senna.         --Boyle.
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         Their souls are immerged in matter.      --Jer. Taylor.
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