The Art of Perfumery, and Methods of Obtaining the Odors of Plants

4 equivalents of alcohol = 46 × 4 = 184, and 23.17936 gallons × 7.93811 lbs. per gallon, also = 184.0003094. Hence it appears that 23.17936 gallons of absolute alcohol are equal to 4 equivalents. By adding the overproof per centage (75.25) to 100, and multiplying by the quantity (23.17936 gallons) we get the constant number 4062.183. The rule might have been calculated so as to show at once the equivalent, without dividing by 4; but it would have required several more places of decimals; it will give the required quantity to a fraction of a fluid drachm. PURIFICATION OF SPIRITS BY FILTRATION.