472 THE POPULAR SCIENCE MONTHLY. 



ganic substance. Such is the brilliant paint, carmine, which is the 

 pigment of the cochineal insect, and the red color of blood, which may 

 be collected in crystals, separate from the other particles to Avhich it 

 is united. 



Even the powder not unknown to ladies of fashion is one of Nature's 

 beautifying means. That which is left on the hands of the ruthless 

 boy, when he has caught a butterfly, is a common instance ; but there 

 are birds, such as the large white cockatoo, which leave a white ]30w- 

 der on the hands. An African traveller speaks of his astonishment on 

 a rainy day to see his hands reddened by the moist plumage of a bird 

 he had just killed. The most ordinary way, however, in which the 

 pigment is found is when it exists in the depths of the tissues reduced 

 to very fine particles, best seen under the microscope. When scattered, 

 they scarcely influence the shade ; but, when close together, they are 

 very perceptible. This explains the color of the negro : under the very 

 delicate layer of skin which is raised by a slight burn there may be 

 seen abundance of brown pigment in the black man. It is quite super- 

 ficial, for the skin differs only from that of the European in tone ; it 

 wants the exquisite transparency of fair races. Among these, the colors 

 which impress the eye do not come from a flat surface, but from the 

 different depths of layers in the flesh. Hence the variety of rose and 

 lily tints according as the blood circulates more or less freely ; hence 

 the blue veins, which give a false appearance, because the blood is red ; 

 but the skin thus dyes the deep tones which lie beneath it ; tattooing 

 with Indian-ink is blue, blue eyes owe their shade to the brown pig- 

 ment whicli lines the other side of the iris, and the muscles seen under 

 the skin produce the bluish tone well known to painters. 



The chemical nature of pigment is little known ; the sun evidently 

 favors its development in red patches. AgQ takes it away from the 

 hair when it turns white, the coloring-matter giving place to very small 

 air-bubbles. The brilliant white of feathers is due to the air which 

 fills them. Age, and domestic habits exchanged for a wild state, alter 

 the appearance of many birds and animals ; in some species the feathers 

 and fur grow white every year before falling off* and being renewed ; 

 as in the ermine, in spring the fur which is so valued assumes a yellow 

 hue, and, after a few months, becomes white before winter. 



It would, however, be an error to suppose that all the exquisite 

 metallic shades which diaper the feathers of birds and the wings of 

 butterflies arise from pigments ; it was a dream of the alchemists to 

 try to extract them. Their sole cause is the play of light, fugitive as 

 the sparkles of the diamond. When the beautiful feathers on the 

 breast of a humming-bird are examined under the microscope, it is 

 astonishing to see none of the shades the mystery of which you would 

 penetrate. They are simply made of a dark-brown opaque substance 

 not unlike those of a black duck. There is, however, a remarkable 

 the barb of the feather, instead of being a fringed 



