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.

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    mannitan, mannitan tetraoetate, mannitan monochlorhydrin are right- rotating ; whilst mannite diehlorhydrin, crystallizable mannitan, and mannitone are left-rotating (Vignon,1 Bouchardat3). By oxidation of dextro-camphor with nitric acid we obtain, simultaneously with right- rotating camphoric and camphic acids, left-rotating camphoromc acid as well (Montgolfier3). Lastly, the remarkable fact must be mentioned that in certain cases active substances exhibit changes in the direction of their rota- tory powers, when dissolved in various liquids or when certain substances are added to their solutions. Asparagin and aspartic acid are left-rotating in alkaline (i.e, sodic, orammoniacal) solutions; but in acid (i.e. hydrochloric or nitric acid) solutions, on the con- trary, they are right-rotating (Pasteur4). The acid ammonium salt of kevo-rotatory malic acid exhibits left-handed rotation in aqueous and ammoniacal solutions; in nitric acid it forms a right-rotating solution (Pasteur4). The calcium salt of dextro-tartaric acid is dextro- rotatory in aqueous and lsevo-rotatory in hydrochloric acid solution; whilst, on the other hand, kevo-tartrate of lime is dextro-rotatory in hydrochloric acid solution (Pasteur5). An aqueous solution of mannite, which, as such, manifests a very feeble left-handed rotation, becomes strongly lsevo-rotatory, on addition to the solution of certain alkalies (as caustic potash, caustic soda, magnesia, lime, baryta), and dextro-rotatory, in presence of salts of the alkalies (as borax, chloride of sodium, sodium sulphate, potassium hydrarseniate). Ammonia renders it feebly dextro-rotatory, but acids have no effect upon it (Yignon,6 Bouchardat,7 Miintz and Aubin8). Similar properties are exhibited to a remarkable extent by ordinary tartaric acid. In aqueous solution it is dextro-rotatory, whilst in the solid state it may assume a kevo-rotatory power (§ 19). The rotatory power of its aqueous solutions is very considerably in- creased by the addition of even small quantities of boric acid, or borax , on the other hand, it is diminished by the addition of sulphuric, hydrochloric, or citric acid, and also of alcohol or wood-spirit (Biot). 1 Vignon: Jahresb. fur Chem. 1874, 885. 2 Bouchardat: Jahresb.fur Chem. 1875, 790—792. 3 Montgolfier : Jahresb. fur Chem. 1872, 569. i Pasteur: Ann. Chim. Phys. [3], 31, 67. Jahresb.fur Chem. 1851, 176. 5 Pasteur: 'Ann. Chim. Phys. [3], 28, 56. Jahresb. fur Chem. 1849, 128. 6 Vignon: Ann. Chim. Phys. [5], 2, 433. Jahresb. fur Chem. 1874, 884. 7 Bouchardat: Comptes Pend. 80, 120. Jahresb. fur Chem. 1875,145. 3 Muntz and Aubin : Ann. Chim. Phys. [5], 10, 553. Jahresb. fur Chem. 1876, 149.