BATES AND JACKSON: QUARTZ-WEDGE SACCHARIMETER 29 



thermostated room with a content of about 15 cubic meters. 

 With two observers in the large thermostat the maximum 

 variations were about 0?3 C. 



The polarization tubes were of glass. Careful measurements 

 established the fact that the tubes filled with distilled water gave 

 a negligible rotation. 



The polariscopic measurements included a long preliminary 

 series and a final series of ten experiments. The latter are given 

 in Table 1 . It will be observed from the values given in column 

 9 that the normal sugar solution gave a rotation of but 99?89 6 -*S 6 

 on a saccharimeter calibrated according to the Herzfeld-Schon- 

 rock' standard. This calibration was obtained by the use of two 

 quartz plates whose absolute rotations and sugar values had 

 been determined by the Reichsanstalt, the Institut fur Zucker- 

 industrie, and also by us. It was, therefore, concluded that the 

 Herzfeld-Schonrock standard was too large by over 0?1 S. 



The data were then recalculated on the basis of the reading 

 of the normal solution which must be 100 ?00 S on the true scale. 

 The sugar values of the two quartz plates were thus compared 

 directly with the normal solution and their sugar values calcu- 

 lated. Since the values of the plates were known in terms of 

 monochromatic light, the new conversion factors followed by 

 direct calculation. For X = 5892.5 A this became 34? 620 and 

 for X = 5461 A it became 40? 690. 



On the same day that the solutions were read on the saccha- 

 rimeters their rotations were also measured on the polarimeter in 

 terms of monochromatic light, X = 5461 A . For this wave length 

 the normal solution caused a rotation of 40? 763. 



The ratios of the rotations of quartz and of sugar solutions for 

 the two wave lengths were determined 



For quartz 



and for sugar 



*ft\ = 5892.5 ,4 

 ^X = 5461 A 



^\= 5892.5 A 



0.85085 



= 0.84922 



X = 5461 A 



6 The symbol S signifies a Sugar Degree, i. e., one-hundredth part of the rota- 

 tion of the normal sugar solution on the saccharimeter. 



