present existing in this country, the various
degrees of strength of brandy, rum, arrack, gin, whiskey, and other
spiritous liquors, chiefly composed of little else than spirit of wine,
are determined by the quantity of alcohol of a given specific gravity
contained in the spiritous liquors of a supposed unknown strength. The
great public importance of this subject in this country, where the
consumption of spiritous liquors adds a vast sum to the public revenue,
has been the means of instituting many very interesting series of
experiments on this subject. The instrument used for that purpose by the
Customs and officers of Excise, is called _Sikes_'s hydrometer,[88]
which has now superseded the instrument called _Clark_'s hydrometer,
heretofore in use.

The specific gravity or strength of the legal standard spirit of the
Excise, is technically called _proof_ or _proof spirit_. "This liquor
(not being spirit sweetened, or having any ingredient dissolved in it,
to defeat the strength thereof,) at the temperature of 57 deg. Faht. weighs
exactly 12/13th parts of an equal measure of distilled water;" and with
this spirit the strength of all other spiritous liquors are compared
according to law.

The strength of spirit stronger than _proof_ or _over proof_, as it is
termed by the revenue officers, is indicated by the bulk of water
necessary to reduce a given volume of it, to the legal standard spirit,
denominated _proof_--namely; if one gallon of water be required to bring
twenty gallons of brandy, rum, or any other spirit, to proof, that
spirit is said to be _1 to 20 over proof_. If one gallon of water be
required to bring 15, 10, 5, or 2 gallons of the liquor to _proof_, it
is said to be 1 to 15, 1 to 10, 1 to 5, and 1 to 2, _over proof_.

The strength of brandy, rum, arrack, gin, or other spiritous liquors,
weaker than _proof_, or under _proof_, is estimated by the quantity of
water which would be necessary to abstract or bring the spirit up to
proof.

Thus, if from twenty gallons of brandy one gallon of water must be
abstracted to bring it to proof, it is said to be 1 in 20 under proof.
If from 15, 10, 5, or 2 gallons of the liquor, 1 gallon of water must be
abstracted to bring it to proof, it is said to be 1 in 15, 1 in 10, 1 in
5, and 1 in 2 under proof.

It is necessary to understand this absurd language, which is in use
amongst the officers of Excise and dealers in spirit, in order to know
what is meant in commerc