To get the least idea of the variety of colours mixing, merging, and intermingling with one another we must go to the opal, though even there there is not the intensity of colour, and of course not the change nor extent. From an orange--especially a blood orange--we get a notion of the combined reds and yellows of the sunsets, though the reds may range deeper than orange into the reds of the ruby or the cardinal flower, and lighter into the pinks of the rose or the carnation; and the yellows range from the gold of the eseholtzia to the delicate hue of the primrose. And for the translucency of their yellower effects we must bring in the amber. Often there is a green which can only be matched by jade or emerald. And sometimes there is an effect with which only the amethyst can be compared. Then there are mauves and purples for which the precious stones have no parallel, and of which heliotrope, the harebell, and the violet give us the best idea. And the blues range from the deep blue of the sapphire and the gentian to the light blue of the turquoise and the forget-me-not. In these stones and flowers we get something near the actual colour, but the depth, the clearness, the luminosity, and the vast extent are all wanting, and these are all essential features of the sunset's glories. So we must imagine all these colours glowing with light and never still--perpetually changing from one to the other and shading off from one into the other, one colour emerging, rising to the dominant position, and then disappearing to give place to another, and effecting these changes imperceptibly yet rapidly also, for if we take our eyes away for even a few minutes we find that the aspect has altogether altered. From my camp in Tibet for weeks together I could be sure of witnessing every evening one of these glorious sunsets. For while the mighty monsoon clouds used to roll up on to the line of Himalayan peaks and pile themselves up there, billow upon billow, in magnificent array, dark and fearful in the general mass, but clear-edged and silver-tipped along the summits, yet beyond that line, in Tibet, the sky was nearly always clear and blue of the bluest. With nothing whatever to impede my view--no trees, nor houses, nor fences, nor obstacles of any kind--I could look out far over these open plains to distant hills; beyond them, again, to Mount Everest a hundred miles away; beyond it, again, to still more distant mountains; and, finally, behind them into the setting sun. And these far hills and snowy mountains, seen as they were across an absolutely open plain, seemed not to impede the view but only to heighten the impression of great distance. The eye would be led on from feature to feature, each receding farther into the distance till it seemed only a step from the farthest snowy mountain into the glowing sun itself.