Tables for Finding the True Percentage by Volume, at the Normal Temperature of 60° F., of Alcohol of Any Strength, when Tested at Temperatures Below or Above 60° F.
Table I.—For Temperatures Under 60° F.
| Per cent of Alcohol by Volume. | Number of F. Degrees Requiring Addition of one to Percentage. | Per cent of Alcohol by Volume. | Number of F. Degrees Requiring Addition of one to Percentage. | |
|---|---|---|---|---|
| 21 | 5·4 | 60 | 5·4 | |
| 22 | 5·175 | 61 | 5·4 | |
| 23 | 4·725 | 62 | 5·4 | |
| 24 | 4·5 | 63 | 5·625 | |
| 25 | 4·5 | 64 | 5·625 | |
| 26 | 4·5 | 65 | 5·625 | |
| 27 | 4·5 | 66 | 5·625 | |
| 28 | 4·275 | 67 | 5·625 | |
| 29 | 4·275 | 68 | 5·85 | |
| 30 | 4·275 | 69 | 5·85 | |
| 31 | 4·275 | 70 | 5·85 | |
| 32 | 4·275 | 71 | 5·85 | |
| 33 | 4·275 | 72 | 5·85 | |
| 34 | 4·275 | 73 | 5·85 | |
| 35 | 4·5 | 74 | 6·075 | |
| 36 | 4·5 | 75 | 6·075 | |
| 37 | 4·5 | 76 | 6·075 | |
| 38 | 4·5 | 77 | 6·075 | |
| 39 | 4·5 | 78 | 6·3 | |
| 40 | 4·5 | 79 | 6·3 | |
| 41 | 4·725 | 80 | 6·3 | |
| 42 | 4·725 | 81 | 6·525 | |
| 43 | 4·725 | 82 | 6·525 | |
| 44 | 4·725 | 83 | 6·75 | |
| 45 | 4·95 | 84 | 6·75 | |
| 46 | 4·95 | 85 | 6·75 | |
| 47 | 4·95 | 86 | 6·75 | |
| 48 | 4·95 | 87 | 6·975 | |
| 49 | 4·95 | 88 | 7·2 | |
| 50 | 5·175 | 89 | 7·425 | |
| 51 | 5·175 | 90 | 7·65 | |
| 52 | 5·175 | 91 | 7·875 | |
| 53 | 5·175 | 92 | 8·1 | |
| 54 | 5·175 | 93 | 8·325 | |
| 55 | 5·175 | 94 | 8·775 | |
| 56 | 5·175 | 95 | 9· | |
| 57 | 5·4 | 96 | 9·45 | |
| 58 | 5·4 | 97 | 10·125 | |
| 59 | 5·4 |
Explanation.—Supposing an alcohol should be found to contain 40 per cent of absolute alcohol by Tralles’ alcoholometer at 45° F. The difference between 45 and 60° F. is 15. Opposite to 40 will be found the figure 4·5. For every 4·5 degrees F. below 60° there must be added 1 to the alcoholic percentage. Hence for 15 degrees there must be added 3.3 degrees. The alcoholic percentage, by volume, therefore, is 43·3 per cent.
Table II.—For Temperatures Above 60° F.
| Per cent of Alcohol by Volume. | Number of F. Degrees Requiring Subtraction of one to Percentage. | Per cent of Alcohol by Volume. | Number of F. Degrees Requiring Subtraction of one to Percentage. | |
|---|---|---|---|---|
| 21 | 5·85 | 61 | 5·175 | |
| 22 | 5·625 | 62 | 5·175 | |
| 23 | 5·4 | 63 | 5·175 | |
| 24 | 5·175 | 64 | 5·175 | |
| 25 | 4·95 | 65 | 5·175 | |
| 26 | 4·95 | 66 | 5·4 | |
| 27 | 4·725 | 67 | 5·4 | |
| 28 | 4·725 | 68 | 5·4 | |
| 29 | 4·5 | 69 | 5·625 | |
| 30 | 4·5 | 70 | 5·625 | |
| 31 | 4·5 | 71 | 5·625 | |
| 32 | 4·5 | 72 | 5·625 | |
| 33 | 4·5 | 73 | 5·625 | |
| 34 | 4·5 | 74 | 5·625 | |
| 35 | 4·5 | 75 | 5·85 | |
| 36 | 4·5 | 76 | 5·85 | |
| 37 | 4·5 | 77 | 5·85 | |
| 38 | 4·5 | 78 | 5·85 | |
| 39 | 4·5 | 79 | 6·075 | |
| 40 | 4·5 | 80 | 6·075 | |
| 41 | 4·5 | 81 | 6·075 | |
| 42 | 4·5 | 82 | 6·075 | |
| 43 | 4·5 | 83 | 6·3 | |
| 44 | 4·5 | 84 | 6·3 | |
| 45 | 4·5 | 85 | 6·3 | |
| 46 | 4·5 | 86 | 6·525 | |
| 47 | 4·725 | 87 | 6·525 | |
| 48 | 4·725 | 88 | 6·525 | |
| 49 | 4·725 | 89 | 6·75 | |
| 50 | 4·725 | 90 | 6·975 | |
| 51 | 4·725 | 91 | 6·975 | |
| 52 | 4·725 | 92 | 7·425 | |
| 53 | 4·95 | 93 | 7·425 | |
| 54 | 4·95 | 94 | 7·65 | |
| 55 | 4·95 | 95 | 7·65 | |
| 56 | 5·175 | 96 | 8·1 | |
| 57 | 5·175 | 97 | 8·1 | |
| 58 | 5·175 | 98 | 8·325 | |
| 59 | 5·175 | 99 | 9·45 | |
| 60 | 5·175 | 100 | 9.9 |
Explanation.—In this case, the same calculation is performed as directed under Table I., except that the correction is to be deducted instead of added.
Aside from the water present in it, commercial alcohol is never pure, but always contains small quantities, at times mere traces, of substances having a peculiar, sometimes pleasant, sometimes disagreeable, but invariably intense odor, which are known as fusel oils. The variety of fusel oil differs with the raw material from which the alcohol was made; there is a potato fusel oil (chemically amyl alcohol), a corn fusel oil, a beet fusel oil, wine fusel oil (œnanthic ether), etc. Fusel oils, being themselves odorous substances, exert an influence on the fragrance of the perfume; hence it is a general rule in perfumery to use only alcohol free from fusel oil; that is, such from which the fusel oil has been extracted as far as possible by means of fresh charcoal. So-called “Cologne Spirit” of the best quality is, as a rule, practically free from it.
Strange to say, some essential oils or aromatic substances in general, develop their finest odors only when the perfumes are prepared with an alcohol from a certain source. While the charcoal treatment removes almost all the fusel oil, the remaining traces suffice to act as odorous substances in the true sense of the term and to produce with other aromatic bodies a harmony of the odor which can never be reached by the use of another variety of alcohol. To give but a single instance we may state that all the citron odors known in perfumery develop the finest aroma only when dissolved in alcohol made from wine and the solution is then distilled. The world-renowned eau de Cologne is made in this way; the other aromatic substances contained in it are added to the distillate from the spirit of wine and the citron oils; any cologne made in another manner or with another alcohol has a less fine odor. While the citron odors require true spirit of wine for the development of their full aroma, other scents require beet or corn alcohol to bring out their best odor. Jasmine, tuberose, orange flowers, violet, etc., and all animal odors (ambergris, musk, and civet) belong to the latter class. For this remarkable and to the perfumer most important fact we know no other explanation than that traces of fusel oils present even in rectified alcohol take part in the general impression made on the olfactory nerves, acting as true aromatic substances.
Cologne spirit is expensive, but this should not be a reason for accepting a cheaper grade, with which it would be absolutely impossible to make really fine perfumes.