So much wealth in Africa has embittered the people. The Dutch farmers, called boers, occupy the heart of the best country. They are not progressive, the English say. Perhaps they mean that the boers do not move away fast enough to suit the English. They have made trek after trek to get out of the way of the English. Trek means journey. But when they realized how much wealth there was about them in the country which they had thought was so poor, they decided not to make any more treks to let the British in. These Dutch farmers withstood the English at Majuba Hill, Jan. 28, 1881, and killed off nearly all the British forces sent against them. In this fight they lost but fourteen men in killed and wounded, while wiping out their enemies. They celebrate this day as we do the Fourth of July. It is their day of independence, and they do not wish to give up the advantage it gave them. Sixty years ago less than five hundred boers under Andries Pretorius defeated twelve thousand Zulus, killing three thousand of them. As the Dutch have such a good reason for trusting to their weapons there is little wonder that the gold and the diamonds of the country brought them into a war with England. LIQUID AIR. Many substances have three forms--solid, liquid, and gaseous. It takes cold to change a gas to a liquid, and more cold to reduce the liquid to a solid. Steam, water, and ice are good examples. Air is a substance that requires so much cold to reduce it even to a liquid state that we know nothing of it as a solid. Our Smithsonian Institution gave Professor Dewar of the Royal Institute of London a gold medal for his discovery in regard to reducing it to a liquid. No artificial cold is intense enough to affect air except when it is confined under great pressure. When a gas is compressed and made cold it tends to liquefy. But it takes enormous pressure and intense cold to make liquid air. It is a grayish substance that may be carried about like water. It has a tendency to steam up, and when its vapor comes into contact with flesh a cooling sensation is produced. But living flesh cannot long remain in contact with the liquid itself. It produces a wound much like a burn. By careful use of liquid air in surgery, the flesh may be so put to sleep that the surgeon's knife is not felt by the patient as he watches the cutting. A cancer has been cut out by liquid air in a sort of burning process that needed no knife. Cremation has been accomplished by its use. Cremation is burning. Burning is the union of oxygen with the substance consumed. Liquid air left exposed to common air evaporates and sends out its nitrogen so that almost pure liquid oxygen is left in the vessel. This placed in contact with the body to be consumed soon sends all except its mineral parts flying away in the atmosphere in a vapor thinner than smoke.