On Sat, 4 Dec 2004 13:57:57 -0500, "B0B" > wrote:

>
>"default" > wrote in message
.. .
>> On Wed, 01 Dec 2004 18:51:50 -0000, (Dick Adams)
>> wrote:
>>
>> >The following URL will take you to a web special sale for an
>> >alcohol hydrometer and test jar. The hydrometer measures both
>> >percentage and proof.
>> >
>> >http://www.alcoholcontrols.com/alhyd.html
>> >
>> > Price Was
>> > ------- -------
>> >Hydrometer $ 29,95 $ 42.95
>> >Test jar 8.95 12.95
>> > ------- -------
>> > $ 38.90 $ 55.90
>> >plus
>> > shipping
>> >
>> >Sounds like a good deal to me. Anyone ever buy one of these?
>> >
>> >
>> >Dick
>> Sounds like Spam to me
>>
>> regular price for a hydrometer and test jar is $6.64 at my usual
>> outlet
>
> This is for an ALCOHOL hydrometer, not a water hydrometer. Note that it
>reads percentage and proof, NOT specific gravity.
> Bob<><

Your statement is incorrect. The hydrometer isn't specific to
alcohol. It is an ordinary hydrometer "marked-calibrated" in
percentage and proof instead of just specific gravity. It can only
measure specific gravity - even if it "reads" in proof.

Sort of like fahrenheit and celsius on a thermometer scale. No magic
- just numbers. Instead of going to a chart to convert the SG to
alcohol you read the proof from the float. (and still correct for
temperature most likely)

But all it really tells you is SG, NOT the alcohol.

To know alcohol with even a hope of accuracy you'd need to know the SG
of the water (assumed to be "one"), the SG of the wort at starting of
fermentation and the finished beer.

But, basically, what they are selling is a high priced hydrometer with
a scale to make it quick and easy to check for pilferage among the bar
staff. (and a very inaccurate one if not temperature compensated)