You're looking for a hydrometer, specifically one for measuring 
ethanol - water mixtures.
But as long as you measure correctly, then why worry? By "measuring 
correctly" I mean separately. Water and ethanol have a curious 
property: when mixed, they make up less volume than their separate 
volumes added. I.e. 50 mL water + 50 mL ethanol make *less* than 100 
mL water-ethanol mixture. I've forgotten the physical chemistry, but 
I'll bet someone on the list knows ...
Phil

>Does anyone know where I can find; and the name of a device; I can use to
>measure the amount of water in graded alcohols?   I believe its a
>hydro.......???
>I'm making up graded alcohol by mathematical formula but still want to check
>that I measured meniscuses correct etc.
>
>
>Ian R. Bernard, SSgt, USAF, AAS, HT (ASCP)
>NCOIC Histopathology/ Pathobiology Laboratory
>59th Clinical Research Sqd / MSROP
>1255 Wilford Hall Loop, bldg 4430
>Lackland AFB, Tx 78236-5319
>
>Tel: 210-292-7190
>Fax: 210-292-6053
>E-mail: Ian.bernard@59mdw.whmc.af.mil

-- 
Philip Oshel
Supervisor, BBPIC microscopy facility
Department of Animal Sciences
University of Wisconsin
1675 Observatory Drive
Madison,  WI  53706 - 1284
voice: (608) 263-4162
fax: (608) 262-5157 (dept. fax)