But I must not forget to say one thing more about Jack in this chapter. While he was studying the subject of birds, he was very fond of getting young ones, so that he might rear them; he also caught several old ones, which he kept in cages. Now I believe that certain birds may be happy in cages, such as canaries, and many others, that are bred in confinement; but to catch wild birds and shut them up, is treating the poor little creatures very cruelly. I would not, therefore, be thought to commend Jack’s example in this respect. [To be continued.] [Illustration] The Deserts of Africa and Asia. In Africa, as well as Asia, there are immense tracts of land called deserts, which consist of vast plains composed of loose sand. Large portions of these are utterly destitute of vegetation, and sometimes, in crossing them, the traveller sees not a hill, or mountain, or human dwelling, or even a tree or shrub, or blade of grass. All around is a sea of sand, and far as the eye can reach, it is one scene of lifeless solitude and desolation. These trackless wastes are traversed by caravans, which are companies of travellers usually mounted upon camels. Horses travel in these sands with difficulty. Their feet sink in the soil; they are overcome with heat, and parched with drought. The camel, on the contrary, has a large spongy foot, which does not sink in the sand; he can bear excessive heat, and by a curious contrivance of nature, is enabled to go without water for five or six days. This valuable creature is called the ship of the desert, because it enables the merchants of Asia and Africa to transport their merchandise over the sea of sand, just as a ship carries goods from one part of the world to another, across the briny ocean. It seems really as if Providence had provided this singular animal on purpose to enable mankind to traverse the great deserts which are spread out upon the eastern continent. The desert of Sahara stretches nearly from the eastern to the western coast of Africa, a distance of almost three thousand miles. Its width is about eight hundred miles. Its whole extent is nearly equal to that of the United States. This vast region, though for the most part a scene of absolute desolation, has a few spots where the water collects in pools, around which some vegetation springs up. These places, which bear a delightful contrast to the surrounding sterility, and cheer the eye of the thirsty, weary traveller, are called _oases_. Here the caravans quench their thirst and repose in the delicious shadow of the trees. The deserts of Arabia are far less extensive, but they are of a similar character to that of Sahara.