"But," he adds, "the uniformity of climate which has led to this rich luxuriance and endless variety of vegetation is also the cause of a monotony that in time becomes oppressive." To quote the words of Mr. Belt: "Unknown are the autumn tints, the bright browns and yellows of English woods; much less the crimsons, purples, and yellows of Canada, where the dying foliage rivals, nay, excels, the expiring dolphin in splendour. Unknown the cold sleep of winter; unknown the lovely awakening of vegetation at the first gentle touch of spring. A ceaseless round of ever-active life weaves the fairest scenery of the tropics into one monotonous whole, of which the component parts exhibit in detail untold variety of beauty." Siberia is no doubt as a rule somewhat severe and inhospitable, but M. Patrin mentions with enthusiasm how one day descending from the frozen summits of the Altai, he came suddenly on a view of the plain of the Obi--the most beautiful spectacle, he says, which he had ever witnessed. Behind him were barren rocks and the snows of winter, in front a great plain, not indeed entirely green, or green only in places, and for the rest covered by three flowers, the purple Siberian Iris, the golden Hemerocallis, and the silvery Narcissus--green, purple, gold, and white, as far as the eye could reach. Wallace tells us that he himself has derived the keenest enjoyment from his sense of colour:-- "The heavenly blue of the firmament, the glowing tints of sunset, the exquisite purity of the snowy mountains, and the endless shades of green presented by the verdure-clad surface of the earth, are a never-failing source of pleasure to all who enjoy the inestimable gift of sight. Yet these constitute, as it were, but the frame and background of a marvellous and ever-changing picture. In contrast with these broad and soothing tints, we have presented to us in the vegetable and animal worlds an infinite variety of objects adorned with the most beautiful and most varied hues. Flowers, insects, and birds are the organisms most generally ornamented in this way; and their symmetry of form, their variety of structure, and the lavish abundance with which they clothe and enliven the earth, cause them to be objects of universal admiration. The relation of this wealth of colour to our mental and moral nature is indisputable. The child and the savage alike admire the gay tints of flowers, birds, and insects; while to many of us their contemplation brings a solace and enjoyment which is both intellectually and morally beneficial. It can then hardly excite surprise that this relation was long thought to afford a sufficient explanation of the phenomena of colour in nature; and although the fact that-- Full many a flower is born to blush unseen, And waste its sweetness on the desert air,