TABLE 126.-Determination of percentage of sucrose in sugar solutions from the readings of the Zeiss immersion refractometer at 20° C1

The values in this table were calculated by J. A. Mathews from the five-place indices of Schönrock as given by Landt, Z. Ver. deut. Zucker-Ind. 83, 692 (1933).

The scale readings refer only to the scale of arbitrary units proposed by Pulfrich, Z. angew. Chem. p. 1168 (1899). According to this scale, 14.5-1.33300, 50.0-1.34650, and 100.0-1.36464. If the immersion refractometer used is calibrated according to another arbitrary scale, the readings must be converted into refractive indices before this table is used to determine the percentage of sugar.

TABLE 127.-Schönrock temperature corrections for determining refractive index of sucrose solutions by means of a refractometer when readings are made at temperatures other than 20° C.

119

106

093

028

014

21 0.00009 0.00010 0. 00011 0. 00011 0. 00012 0. 00013 0. 00013 0. 00014

028

058

073

088

103

119

150

166

232

TABLE 127.-Schönrock temperature corrections for determining refractive index of sucrose solutions by means of a refractometer when readings are made at temperatures other than 20° C-Continued

TABLE 128.- Method of obtaining -log T

Log T for values of T from T=1.00 to T=0.100 may be taken directly from the table of mantissas below. For this range the characteristic is zero. Log T for values of T between T=0.100 and T=0.0000 is obtained by taking from the table of mantissas the decimal part of the logarithm corresponding to the number without regard to the position of the decimal point in the number and adding thereto the appropriate characteristic.

It should be remembered that if T is expressed as the fractional part of unity

TABLE 128.--Method of obtaining -log T-Continued

the characteristic is equal to minus the number of zeros between the decimal point and the first significant figure. Thus, the characteristic of T=0.5 is 0; that of T=0.005 (0.5 percent) is -2; etc.

EXAMPLE 1. To find -log T if T=0.00543. In the table of mantissas the mantissa corresponding to 543 (disregarding the position of the decimal point) is -0.26520. Since there are two zeros between the decimal point and the first significant figure the characteristic is -2. Adding these, log T= -2.26520 and -log T +2.2652.

=