It is possible by applying a little oil to the upper part of the bulb of a common or of a Sikes's hydrometer, and carefully placing it in pure water, to cause it to float with the upper part of the bulb and the whole of the stem emerging as indicated in fig.
- Sikes's longed so as to contain only 10 of these divisions, Hydrometer.
Sikes's hydrometer, on account of its similarity to that of Bories, appears to have been borrowed from that instrument.
The following table gives the specific gravities corresponding to the principal graduations on Sikes's hydrometer at 60° F.
The merit of Sikes's system lies not so much in the hydrometer as in the complete system of tables by which the readings of the instrument are at once converted into percentage of proof-spirit.
Table showing the Densities corresponding to the Indications of Sikes's Hydrometer.
In the above table for Sikes's hydrometer two densities are given corresponding to each of the degrees 20, 30, 40, 50, 60, 70, 80 and 90, indicating that the successive weights belonging to the particular instrument for which the table has been calculated do not quite agree.
A table which indicates the weight per gallon of spirituous liquors for every degree of Sikes's hydrometer is printed in 23 and 24 Vict.
This table differs slightly from that given above, which has been abridged from the table given in Keene's Handbook of Hydrometry, apparently on account of the equal divisions on Sikes's scale having been taken as corresponding to equal increments of density.
Sikes's hydrometer was established for the purpose of collecting the revenue of the United Kingdom by Act of Parliament, 56 Geo.
C. 140, by which it was enacted that "` all spirits shall be deemed and taken to be of the degree of strength which the said hydrometers called Sikes's hydrometers shall, upon trial by any officer or officers of the customs or excise, denote such spirits to be."
C. 28, which established Sikes's hydrometer on a permanent footing.
It is the practice of the officers of the inland revenue to adjust Sikes's hydrometer at 62° F., that being the temperature at which the imperial gallon is defined as containing 10 lb avoirdupois of distilled water.
Keene, of the Hydrometer Office, London, has constructed an instrument after the model of Sikes's, but provided with twelve weights of different masses but equal volumes, and the instrument is never used without having one of these attached.
When loaded with either of the lightest two weights the instrument is specifically lighter than Sikes's hydrometer when unloaded, and it may thus be used for specific gravities as low as that of absolute alcohol.
It resembles Sikes's hydrometer in other respects, but is provided with eight weights.
The use of Sikes's hydrometer necessitates the employment of a considerable quantity of spirit.