Rarefy
Rarefy (rar"e*fī; 277) , transitive verb
[French raréfier; Latin rarus rare + -ficare (in comp.) to make; compare Latin rarefacere. See -fy.]
To make rare, thin, porous, or less dense; to expand or enlarge without adding any new portion of matter to; -- opposed to condense.
Rarefy , intransitive verb
To become less dense; to become thin and porous.
Earth rarefies to dew.