This section is from the book "A Treatise On Beverages or The Complete Practical Bottler", by Charles Herman Sulz. Also available from Amazon: A Treatise On Beverages.
Ethyl buty-rate, eighty parts; ethyl acetate, fifteen parts; vanilla tincture, five parts; tincture of orris root, fifteen parts; alcohol, 1000 parts Mix and add oil of lemon, six grains; oil of cinnamon, six grains; balsam Peru, three grains; oil of neroli, one grain; oil of birch, two grains. When all is dissolved add 200 grains orange-flower water. Rectify in glass retort or clarify with pumice stone, etc. The commercial essence is colored with sugar coloring. A plainer essence is prepared by adding only one drachm of oil of birch, and leave the other oils out. From two pints and upwards of this essence to a barrel of twenty-five gallons diluted aclohol is used, and some sugar coloring. The rum is best prepared in advance, kept in stock in closed barrels for a few months, when it will assume a harmonious aroma, and is generally improved by age. The addition of some prune juice (one gallon) and five to ten gallons of genuine rum to the imitation of twenty-five gallons, gives a higher grade of rum.