Twaddell \Twad"dell\, n., Twaddell's hydrometer \Twad"dell's
hy*drom"e*ter\ [After one Twaddell, its inventor.]
A form of hydrometer for liquids heavier than water,
graduated with an arbitrary scale such that the readings when
multiplied by .005 and added to unity give the specific
gravity.
[Webster 1913 Suppl.]