=56. The Balling or Brix Hydrometer.=—The object of the balling or brix instrument is to give in direct percentages the solid matter in solution. It is evident that for this purpose the instrument must be graduated for a particular kind of material, since ten per cent of sugar in solution, might have a very different specific gravity from a similar quantity of another body. Instruments of this kind graduated for pure sugar, find a large use in technical sugar analysis. To attain a greater accuracy and avoid an instrument with too long a stem, the brix hydrometers are made in sets. A convenient arrangement is to have a set of three graduated as follows; one from 0° to 30°, one from 25° to 50°, and one from 45° to 85°. When the percentage of solid matter dissolved is over seventy the readings of the scale are not very reliable. =57. Correction for Temperature.=—The brix as the baumé scale is graduated at a fixed temperature. This temperature is usually 17°.5. The following table shows the corrections to be applied to the scale reading when made at any other temperature:[33] PER CENT OF SUGAR IN SOLUTION. 0. 5. 10. 15. 20. 25. 30. 35. 40. 50. 60. 70. 75. Temp. _To be subtracted from the degree read._ 0° 0.17 0.30 0.41 0.52 0.62 0.72 0.82 0.92 0.98 1.11 1.22 1.25 1.29 5° 0.23 0.30 0.37 0.44 0.52 0.59 0.65 0.72 0.75 0.80 0.88 0.91 0.94 10° 0.20 0.26 0.29 0.33 0.36 0.39 0.42 0.45 0.48 0.50 0.54 0.58 0.61 11° 0.18 0.23 0.26 0.28 0.31 0.34 0.36 0.39 0.41 0.43 0.47 0.50 0.53 12° 0.16 0.20 0.22 0.24 0.26 0.29 0.31 0.33 0.34 0.36 0.40 0.42 0.46 13° 0.14 0.18 0.19 0.21 0.22 0.24 0.26 0.27 0.28 0.29 0.33 0.35 0.39 14° 0.12 0.15 0.16 0.17 0.18 0.19 0.21 0.22 0.22 0.23 0.26 0.28 0.32 15° 0.09 0.11 0.12 0.14 0.14 0.15 0.16 0.16 0.17 0.17 0.19 0.21 0.25 16° 0.06 0.07 0.08 0.09 0.10 0.10 0.11 0.12 0.12 0.12 0.14 0.16 0.18 17° 0.02 0.02 0.03 0.03 0.03 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.06