Letter | Published:

The Rotatory Dispersion of Tartaric Acid

Nature volume 114, page 122 (26 July 1924) | Download Citation



LONGCHAMBON (C.R. Acad. Sc., vol. 178, p. 951,1924) has recently found that the rotatory dispersion along the optic axes of crystalline tartaric acid is approximately the same as that of the laevo-rotatory component which contributes to the anomalous rotatory dispersion shown by solutions of the acid. The rotatory dispersion here referred to is measured by the ratio between the rotations for the blue (436) and yellow (578 ) lines of mercury. For the crystals it is 2·14, while for the laevo-component in solution it is estimated to lie between 2 and 2·22. From previous researches Longchambon had concluded that the rotatory dispersion of a given substance is a property which is conserved when the substance passes from the solid to the liquid state by fusion or solution. Applying now this generalisation to the case of tartaric acid, he states: “Le constituant gauche ne serait done ni un anhydride ni un éther interne; ce serait l'acide tartrique ordinaire, tel qu'il se trouve dans le cristal; je l'appelerai acide tartrique. J'appelerai le corps droit acide tartrique; c'est la formation de cet acide de l'acide a, par dilution ou élévation de température, qui produit les anomalies de dispersion rotatoire.”

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  1. Davy-Faraday Research Laboratory, Royal Institution, Albemarle St., W.1, July 7.

    • W. T. ASTBURY


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