173 



Table of Corrections for the Temperature. 



Temperature 

 of the 

 Prisms 

 in°C. 



Dry Substance. 



5 10 15 20 25 30 I 40 50 60 



70 80 90 



Subtract. 



0.53 



0.54 



0.55 



0.56 



0.57 



0.58 



60 



0.62 



0.64 



0.62 



0.61 



0.60 



0.58 



0.46 



0.47 



0.48 



0.49 



0.50 



0.51 



0.52 



0.54 



0.56 



0.54 



0.53 



0.52 



0.50 



0.40 



0.41 



0.42 



0.42 



0.43 



0.44 



0.45 



0.47 



0.48 



0.47 



0.46 



0.45 



0.44 



0.33 



0.33 



0.34 



0.35 



0.36 



0.37 



0.38 



0.39 



0.40 



0.39 



0.38 



0.38 



0.38 



0.26 



0.26 



0.27 



0.28 



0.28 



0.29 



0.30 



0.31 



0.32 



0.31 



0.31 



0.30 



0.30 



20 



0.20 



0.21 



0.21 



0.22 



0.22 



0.23 



0.23 



0.24 



0.23 



0.23 



0.23 



0.22 



0.12 



0.12 



0.13 



0.14 



0.14 



0.14 



0.15 



0.15 



0.16 



0.16 



0.16 



0.15 



0.14 



0.07 



0.07 



0.07 



0.07 



0.07 



0.07 



0.08 



0.08 



0.08 



0.08 



0.08 



0.08 



0.07 



0.07 



0.07 



0.07 



0.07 



0.07 



0.07 



0.08 



0.08 



0.08 



0.08 



0.08 



0.08 



0.12 



0.12 



0.13 



0.14 



0.14 



0.14 



0.15 



0.15 



0.16 



0.16 



0.16 



0.15 



0.20 



0.20 



0.21 



0.21 



0.22 



0.22 



0.23 



0.23 



0.24 



0.23 



0.23 



0.23 1 



0.26 



0.26 



0.27 



0.28 



0.28 



0.29 



0.30 



0.31 



0.32 



0.31 



0.31 



0.30 



0.33 



0.33 



0.34 



0.35 



0.36 



0.37 



0.38 



0.39 



0.40 



0.39 



0.38 



0.38 1 



0.40 



0.41 



0.42 



0.42 



0.43 



0.44 



0.45 



0.47 



0.48 



0.47 



0.46 



0.45 



0.46 



0.47 



0.48 



0.49 



0.50 



0.51 



0.52 



0.51 



0.56 



0.54 



0.53 



0.52 



0.07 

 0.14 

 0.22 

 0.30 

 0.38 

 0.44 

 0.50 



Example: Desired, the dry substance of a sample whose refractive 

 index is 1.45S9 taken at 26° temperature. The nearest index is 1.4567. 

 which equals 67% then 1.4589 minus 1.4567 (the nearest value in the 

 table lower than it) =.0022. In the decimal column opposite look for 

 .0022 and one finds a value of 0.95. So the reading is 67.95 but at a tem- 

 perature of 26° (from the table of corrections) .16 must be subtracted 

 or the correct dry substance would be 67.79. In like manner the dry sub- 

 stance of a sample with a refractive index of 1.5021 at 2S° C. would be 

 85.05, and one of 1.3S02 at 2S° would be 30.1, and one of 1.3655 at 33° C. 

 would be 22.06. 



Bureau of Chemistry, 

 Dept. of Agriculture. 

 Washington. D. O, 



