Handbook of the polariscope and its pracitcal applications / adapted from the German editon of H. Landolt, by D.C. Robb and V.H. Veley.

  • Hans Heinrich Landolt
Date:
1882
Catalogue details

Licence: Public Domain Mark

Credit: Handbook of the polariscope and its pracitcal applications / adapted from the German editon of H. Landolt, by D.C. Robb and V.H. Veley. Source: Wellcome Collection.

    89/320 (page 69)
    than the true specific rotation of pure oil of turpentine (37-01), differ- ing from the latter in proportion to the diluteness of the solutions employed in its determination. Thus, with alcohol as the inactive solvent, we get— From mixtures I. and II. A — 36*93° „ II. „ III. A = 36*79° „ III. „ IY. A = 36*66° ,, IV. „ V. A = 35*87° Divergence from 37*01 -0*80° -0*22° -0*35° -1*14° Extra- polation 10 per cent. 30 „ 50 „ 70 On the other hand, if we adopt the formula [a] = A + B q + C q2, and compute the values of the constants A, B, and C from the solutions containing the smallest, mean, and largest proportions respectively of the inactive constituent, we get for A a value approaching very near to that of the specific rotation of pure oil of turpentine. Moreover, the formula agrees sufficiently well with the experimental curve throughout (from q — 10 to 90). The mixtures specified furnished the results shown below :— 1. Alcohol (computed from solutions I., III., and V.) [a]D = 36 974 + 0-0048164 q + 0-00013310 q3. 2. Benzene (computed from solutions I., IY., and VII.) [a]D = 36-970 + 0-021531? + 0-000066727 ?3. 3. Acetic acid (computed from solutions I., IY., and YI.) [a]D = 36-894 + 0-024553 q + 0-00013689 q2. These formulse give the following interpolation values :— Solvent Medium. No. of Mixture. q- Mb Observed. Mb Calculated. Difference. Alcohol | II. 30*0584 37-247° 37-239° - 0-008° IV. 70*0285 37-904° 37-964° + 0-060° II. 22*0728 37-487° 37-478° - 0-009° i III. 34*9447 37-803° 37-804° + 0-001° Benzene \ V. 63*1013 38*523° 38-594° + 0-071° * YI. 77*0443 39*031°' 39-025° - 0-006° , II. 21-9342 37-406° 37'498° i + 0-092°. Acetic Acid < III. 35-1390 37-885° 37-926° + 0-041° ( Y. 77-0384 39-672° 39-598° - 0-074°