citrometern.

1823 Act 4 Geo. IV c. 69 §iii. 525 Such Degrees of such specific Gravity or Strength shall be ascertained by a Glass Citrometer, which shall be graduated in Degrees in such Manner that Distilled Water being assumed as Unity, at the Temperature of Sixty Degrees by Fahrenheit's Thermometer, every Degree of the Scale of such Citrometer shall be denoted by a Variation of Four One thousandth Parts of the Specific Gravity of such Water.

1875 Jrnl. Chem. Soc. 28 930 Lemon-juice..is boiled down in copper vessels over an open fire till it is supposed to mark when cold 60° on the citrometer.

1890 W. S. Jones in B. M. Lelong Culture of Citrus in Calif. 244 Formerly a citrometer, known as Rouchetti's gauge, was used to ascertain the per cent of acidity; now, however, resort is had to chemical analysis.

1928 Daily News (Perth, W. Austral.) 5 May 8/2 The lemon juice from Sicily is prepared by pressing the inferior fruit... The so-called ‘simple’ juice is then boiled down till its sp. gr. equals 60 deg. on the citrometer.

1963 Bottling (Brewing Trade Rev.) Apr. 75/1 Citrometers appear principally to have been used for checking the specific gravity of stock or working solutions of citric acid and sometimes other edible acids.