56 SCIENCE FROM AN EASY CHAIR 



him an oil-painting of a gentleman in a black coat which 

 when wetted with a sponge turned bright blue. The 

 picture had been recently " restored," and the varnish on 

 the black coat was not " dry." It was precipitated by 

 the water from the sponge, mixing with the spirit which 

 held it in solution. A fine colourless cloud was thus 

 produced overlying the black paint of the coat, and, as in 

 the case of the cerulean frog, a dead-blue colour, due to 

 reflection of the light by the fine particles, was the result. 

 Some friendly physicist might repeat this experiment and 

 study the matter in detail. The red, orange, and yellow 

 colours of birds' feathers are produced by pigments which 

 are either insoluble or only soluble with great difficulty 

 in fluids of the nature of ether. There is, however, an 

 exception in the case of the African birds called Turacous, 

 or Plantain-eaters. These birds have some large quill- 

 feathers in the wing of a rich crimson colour. This 

 splendid red pigment can be washed out of the feathers 

 by water which is slightly alkaline, and a fine blood-red 

 solution is obtained. Why this curious exception exists 

 we do not know. The extracted colour is found to 

 contain the element copper as one of its chemical com- 

 ponents. Plantain-eaters kept in cages have sometimes 

 washed all the colour out of their feathers owing to the 

 water supplied to them for bathing and drinking having 

 become foul and ammoniacal, and thus capable of dis- 

 solving the red pigment 



The cultivation on the Riviera of flowers for sale as 

 "cut flowers" in Paris, London, and Berlin, in the colder 

 months of the year, is now an enormous business, bringing 

 many thousands of pounds yearly to the small gardeners 

 around Hyeres, St. Raphael, Nice, and Mentone. Roses, 

 violets, carnations, " mimosa " of various kinds, anemones, 

 lilies, and narcissus are sent literally in tons by quick 

 trains several times a week from these realms of sunshine 



