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In 1888 Russell and Abney published the results of a series of experiments on the influence of light on watercolours. Samples were exposed on Whatman Paper to mixed sunlight and daylight equivalent at least to 480 years of exposure to daylight in exhibition galleries. The following is a list of pigments in order of stability commencing with the lease stable: carmine, crimson lake, purple madder, scarlet lake, Payne's grey, naples yellow, olive green, indigo, brown madder, gamboge, Vandyke brown, brown pink, indian yellow, cadmium yellow, Leitch's blue, violet carmine, purple carmine, sepia, aureolin, rose madder, permanent blue, antwerp blue, madder lake, vermilion, emerald green, burnt umber. Pigments which did not show any change after exposure are the following: yellow ochre, indian red, burnt sienna, chrome yellow, lemon yellow, raw sienna, terre velte, chromium oxide, prussian blue, cobalt, french blue, ultramarine ash. After exposure to dry air, to wet air, to hydrogen, under vacuum, under coloured glass etc, Russell and Abney came to the following conclusions, among others, that the presence of humidity and oxygen is, in general, essential for fading. The blue and near violet end of the spectrum produce the most important changes. The article ends by giving some of the consequences of the report. G. Thomson