Some shielding and deshielding effects by an adjacent cyclopropyl ring and the effect of the ring on geminal coupling constants M -to the ring are reported and discussed.* Some part of these changes in shift may be due, for example, to differences in the structure of the dioxan ring induced by the cyclopropyl ring attached to it. * Geminal coupling constants are generally negative, although we have not confirmed this in the present case. Thus 'augmentation of the numerical value' means a more negative coupling constant t This they term a hyperconjugation effect and the calculation is borne out by experimental values which they quote.