When determining the specific gravity of a saline solution by the hydrometric method, it is necessary first to find the weight which must be added to the hydrometer to immerse it to the 50-mm. mark when floating in the saline solution at the chosen standard temperature. This added weight is found by a series of observations in exactly the same manner as with the hydrometer in distilled water (see § 14 et seq.).

The details of three series of observations with hydrometer No. 17 in a solution of ⅛ gram-molecule of cæsium chloride in 1000 grams of water at 19·50° are given as an example in Table C. This table is arranged in the same manner as Table A1.