pounde. CHARLES MOUREU (Compt. Fend., 1905, 141, 892-895).- The author has measured the molecular refraction and dispersion of 30 acetylenic compounds (compare Abstr., 1902, i, 253, 289 ; 1903, i, 312, 698 ; 1904, i, 285, 286,650, €ill), and in the original the differences between the observed values and those calculated from the sum of the atomic refractions are recorded. I f M represents the observed molecular refraction for the D line of sodium and C represents the corresponding calculated

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... lue, then the effect of the acetylenic linking, measured by M -C , is found t o be constant for members of a homologous series, but to vary with different types of compounds, increasing with the number of negative groups in the molecule and their proximity to the acetylenic linking ; thus, for heptinene, CH,*[CH2],-CiCH, and octinene, CH,*[CH,],-CiCH, M -C has the minimum values 2.338 and 2.301 respectively, whilst the corresponding value for diphenyldiacetylene, CPhiC*CiCPh, is 17,494 (compare Briihl, Abstr., 1894, ii, 432 ; Haller and Muller, Abstr., 1899, i, 770 ; ii, 622 ; 1904, ii, 221 ; Muller, Abstr., 1902, i, 354 ; Muller and Bauer, Abstr., 1904, ii, 705). M. A. W.