Field's alcoholometer, since improved by Ure, is based upon this principle.
I have never attempted to collect quantities of alcoholics without an alcoholometer in constant use.
Therefore I say, buy an alcoholometer at all hazards, and carry it and a suitable test-glass with your outfit.
This instrument is sometimes called Richters alcoholometer, in England.
The spirit used should be reduced to about proof, and the traveller should always be provided with an alcoholometer.
