NEGRETTI AND ZAMBEA, HOLBORN VIADUCT, B.C., 



FIG. 425*. 



FIG. 425. 



s. 



424 Government Proof Hydrometer, Glass, showing percentages of proof 



spirit from 60 over proof to 40 under proof (fig. 397) . . .056 



425 Ditto ditto Hydrometer, Glass, in mahogany box with Thermometer 



(fig. 398) with Printed instructions for use 15 



426 Ditto ditto, with Ivory sliding Computing Scale . .110 

 427 Sikes'* Hydrometer is the instrument used by the government officers in 



the collection of the spirit revenue in the United Kingdom. It is made entirely of 

 metal, usually strongly gilt to prevent corrosion. 



It consists of a globular float with an upper and lower stem. The upper stem 

 is flattened and divided into ten parts, numbered 1, 2, 3, &c. These are again sub- 

 divided into five parts. 



The lower stem is tapering, and terminating by a pear-shaped bulb. There are 

 nine weights numbered from 10 to 90, each weight being pierced in the centre, so 

 that it can be placed on the conical stem at the smaller end and slid down towards 

 the bulb until it becomes securely fastened. 



428. Sikes' Hydrometer is adjusted to spirit Specific Gravity -825 at 60 Q Fahr., 

 this being considered Standard Alcohol. In this spirit the instrument floats at the 

 first division on the stem without a weight. In weaker spirit, having a greater 

 density, the Hydrometer will not sink so low, and should the density be greater, 

 one of the weights must be added to cause the entire immersion of the bulb of the 

 instrument. 



Each weight represents so many principal divisions of the stem. Thus the 

 heaviest weight, marked 90, is equal to ninety divisions of the stem, and the instru- 

 ment with this weight attached floats at in distilled water. 



Each principal division on the stem being divided into five, the Hydrometer 

 has a range of 500 degrees between alcohol, sp. gr. '825 and water. 



On one side of the upper stem, near to the division 1, will be found a line, at 

 which the instrument will float with the weight 60 attached in spirit exactly of the 

 strength of proof at a temperature of 51 Fahr., and if the square weight (sent with 

 the instrument) be placed on the top of the stem, the weight 60 still being attached 

 to the lower stem, the instrument will float at the side line in distilled water of the 

 same temperature. This square weight being precisely one-twelfth part of the total 

 weight of the hydrometer and weight 60, the above indication is in conformity 

 with the definition of proof spirit stated in the act of parliament, " Proof spirit 

 to weigh at 51 temperature exactly twelve-thirteenth parts of an equal bulk of 

 distilled water." 



In using Sikes' Hydrometer, it is immersed in the spirit and pressed down 

 to until the whole of the divided stem be wet. The amount of force required to 



* We have consulted several authorities for the correct spelling of this name ; Dr. Tire and Professor 

 Redwood spell it Sikes. An act of parliament, 26th June, 1858, 18 and 19 Viet., has Sykes many writers 

 adopt this. The same difference occurs with the name of the inventor of a Maximum and Minimum 

 Registering Thermometer Six or Sixe. In both cases there appears to be some doubt which is correct. 



