Notices of the proceedings at the meetings of the members of the Royal Institution of Great Britain with abstracts of the discourses . ts. That carbon atom which was present in the originalmethane molecule is, in these new compounds, now attached to fourdifferent atomic groups, and such a carbon atom is termed an asym-metric carbon atom. It is in the case of substances containing anasymmetric carbon atom that a lack of agreement is observedbetween the facts and the kind of isomerism indicated by the Kekuleformulfe, and in these cases also the species of isomerism indicatedby the solid models e
Notices of the proceedings at the meetings of the members of the Royal Institution of Great Britain with abstracts of the discourses . ts. That carbon atom which was present in the originalmethane molecule is, in these new compounds, now attached to fourdifferent atomic groups, and such a carbon atom is termed an asym-metric carbon atom. It is in the case of substances containing anasymmetric carbon atom that a lack of agreement is observedbetween the facts and the kind of isomerism indicated by the Kekuleformulfe, and in these cases also the species of isomerism indicatedby the solid models exhibited is found to correspond closely withthe facts. To illustrate this, we may refer to a somewhat complicatedsubstance termed tetrahydroquinaldine, which has the appended con-stitution and the molecule of which contains an asymmetric carbon H H H «J V HhV V Vh I II IH-C C C—H% / \ S\C N CHI IH H Tetrahydroquinaldine. atom, that, namely, which is printed in heavy type. Three differentisomeric forms of this substance exist and are quite indistinguishableby any of the ordinary methods of chemical or physical identification ;. Fig. 5. Fig. 6. one of these is a loose kind of compound of the other two, and maytherefore be disregarded for the moment. The remaining two have thesame melting point, the same boiling point and correspond exactly inall ordinary properties; they yield, however, series of derivatives 306 Professor William J. Pope [May 1, which differ in the same sort of way that a right-hand and a left-hand glove differ. Here, for instance, is a diagram showing theshapes of the crystals which these two substances form with hydro-chloric acid (Figs. 5 and 6); the crystals obtained from the onebase are the mirror-images of those prepared from the other. Anyfigure which possesses handedness of the kind exhibited by thesetwo crystal figures is termed enantiomorphous, and two figureswhich are related to each other as these figures are related are saidto be enantiomorphously
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