Over Proof (O.P.)—each degree means 1 per cent. of water required to be added to bring the spirit down to proof.
The scale of Tralles’s alcoholometer only differs from Gay-Lussac’s by water being taken at 39·2° and pure alcohol as of sp. gr. 7939 at 60°.
| Alcohol | Sykes° | Baumé° | ||||
| Sp. Gr. | Vol. per cent. | (Excise) | (French) | |||
| 1·000 | 0 | 100 U.P. | 10 | |||
| 0·920 | 57·05 | Proof | 22 | |||
| 0·848 | 85·2 | 49·6 O.P. | 36 | Fr. Rect. Spirit Troix-six. | ||
| 0·838 | 88·8 | 55·8 „ | 38·2 | Rect. Spirit, Brit. Pharm. | ||
| 0·821 | 93·75 | 64·3 „ | 41·8 | Strongest Rect. Spirit. | ||
| 0·794 | 100 | — | 48 | Absolute Alcohol. | ||
The approximate relation of the five usual scales for proof and French rectified spirit are as follows:
| Proof 0·920 | Fr. Rect. Sp. 0·848 | |||
| Gay-Lussac | 58° | 86° | ||
| Tralles | 56·3° | 85° | ||
| Cartier | 21·6° | 34° | ||
| Baumé | 22·6° | 36° Trois-six | ||
| Sykes | Proof | 49·6° | ||
Compound Industrial Units
Units of Power, of Electricity, of Caloric, &c., are abstract compound units based on units of time, weight, length, &c., combined for industrial convenience, e.g. a certain weight moved a certain distance in a certain time.
The H.P., engine horse-power, is 550 lb. raised one foot in one second. In France this becomes 75·9 kilos, raised one metre in one second, = about 3/4 of the kilo-watt unit of electric power.
[43]. Normal body-temperature is taken in France as 37° C. In Germany it is taken as 29·3° Réaumur = 97·9° F.