NOTES.--The following Azo colours, reported upon last year, were exposed after having been applied as acid-colours: Hessian Yellow, Chrysamine R and G, Cresotin Yellow G, and Carbazol Yellow. Those exposed during the past year, and reported upon now, were applied upon chromium mordant. The results now obtained show that all these colours when dyed on chromium mordant are distinctly faster to light than when dyed as acid-colours. An important additional advantage of the chromium colours is that even after a year's exposure the faded colours appear level, showing none of the speckled appearance so frequently noticed with the faded colours dyed by the acid method. When these colours are applied on aluminium and tin mordants they are more fugitive, and may then be classed as 'fast' or 'moderately fast.' It may be noticed that Madder, Munjeet, and Purpurin give faster colours with tin than with aluminium mordant. SILK PATTERNS. All the foregoing colours were also dyed on silk, and the patterns were exposed to light, along with those on wool, with the result that the relative fastness of the various colours was practically the same as on wool. The only exceptions were the colours obtained from Morinda-root and from Kamála. Morinda yellow, dyed without the aid of any mordant, is much faster on silk than on wool, and although the colour becomes brownish during exposure, it may be classed as 'fast' on silk. The Indian dyestuff Kamála was reported upon last year and classed as a 'fugitive' colour. This year the orange-yellow colour exposed was obtained by applying it in conjunction with alum, and found to be much faster than the colour obtained by dyeing in a simple alkaline bath (NaCO3). A sample of the rich red-orange colour dyed in India was also exposed. Both dyes examined this year may be classed as 'moderately fast.' Isomeric Naphthalene Derivatives.-Ninth Report of the Committee, consisting of Professor W. A. TILDEN and Professor H. E. ARMSTRONG. (Drawn up by Professor ARMSTRONG.) In previous reports reference has frequently been made to the trichloronaphthalenes during the past year Dr. Wynne and the writer have at length completed their examination of this series, and have satisfied themselves of the existence of 14, but only 14, such compounds, which is in accordance with theory. A complete table of the 14 trichloronaphthalenes having been published in the Chemical Society's Proceedings,' No. 151, 1895, p. 85, it is unnecessary here to further refer to them. It may be mentioned that the series is the largest hitherto known isomeric series. In completing the work on this subject not only have numerous preparations been required, but it has been necessary also to make many chlorine determinations, and the grant has been expended chiefly on these latter. I am specially indebted to Mr. R. L. Jenks for his assistance in the analytical work. Wave-length Tables of the Spectra of the Elements and Compounds.- Rowland: Astronomy' and 'Astro-Physics,' 1893, xii. 321. * Beginning of head of A, outside edge. † Single line at the beginning of the tail of A. 1895. T |