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.

    101/320 (page 81)
    For Alcohol [a]D = 8-409 + 0*018667 q „ Wood-Spirit [a]D = 8-418 + 0-062466 q - 0-00034786 (/ „ Water [<*]„ = 8-090 + 0-20032 q is shown in the table annexed :—- Solvent. No. of Mixture. Y Md Observed. l M Calculated. Difference. ( I. 22-0226 8-780° 8-820° + 0-040 Alcohol < II. 64-2634 9-618° 9-609° - 0-009 ( III. 77-6703 9-846° 9--859° + 0-013 Wood Spirit j II. 43-3473 10-411° 10-472° 'fe 0-061 IY. 73-0319 11-070° 11-124° + 0-054 ( I. 30-3133 14-001° 14-162° + 0-161 Water j II. 60-1795 20-220° 20-145° - 0-075 ( III. 86-1136 25-200° 25-340° + 0-140 Inferences. § 34. The results of the investigations detailed in the previous sections may be stated as follows:— 1. The Rate of Change in the Specific Rotation of an Active Sub- stance, when progressively diluted with some Inactive Liquid, is gradual throughout.—The nature of the change,whether an increase or decrease, will depend on the nature of the active substance : thus, oil of turpen- tine and ethyl tartrate, in whatever liquids dissolved, always exhibit an increase, whilst nicotine and camphor (for which see § 36), on the other hand, exhibit a decrease in the amount of their specific rotation. Moreover, the rates of variation produced by increasing quantities of different solvents with the same active substance are very different, so that if we represent them graphically we shall have a series of curves radiating from the common point which represents the rotation of the pure substance. Thus the more dilute any solution of an active substance, the more will its specific rotation differ from that of the absolute substance; and the total amount of possible variation may be shown by putting in the interpolation-formulae the limiting values q — 0 (absolute sub- stance), and q = 100 (maximum of dilution). Taking the substances