Page:The wonders of optics (1869).djvu/26

 The vivacity or languor of the movement of the eyes forms one of the chief characteristics of facial expression, and their colour helps to render this characteristic more striking. The different colours seen in the eye are dark hazel, or black, as it is generally called, light hazel, blue, greenish grey, dark grey, and light grey. The velvety substance which gives the colour to the iris is arranged in little ramifications and specks, the former being directed towards the centre of the eye, the latter filling up the gaps between the threads. Sometimes they are both arranged in so regular a manner that instances have been known in which the irises of different eyes have appeared to be so much alike that they seemed to have been copied from the same design. These little threads and specks are held together by a very fine network.

The commonest colours seen in the eye are hazel and blue, and it mostly happens that both these colours are found in the same individual, giving rise to that peculiar greenish-grey hue that is far from being uncommon. Buffon thinks that blue and black eyes are the most beautiful, but this of course is a matter of taste. It is true that the vivacity and fire which play so important a part in giving character to the eye, are more perceptible in dark eyes than in those whose tints are lighter; black eyes, therefore, have greater force of expression, while in blue eyes there is more softness and delicacy. In the former we see a brilliant fire, which sparkles uniformly on account of the iris, which is of the same colour throughout, giving in all parts the same reflection; but a great difference may be perceived in the intensity of the light reflected from blue eyes, from the fact of the various tints of colour producing different reflections. There are some eyes that are remarkable for being almost destitute of colour, and appear to be constituted in an abnormal manner. The iris is tinted with shades of blue and grey of so light a hue that it appears quite