4. Alcohol of the greatest purity and strength is the best fuel, and is most easily transported in vessels containing about ten gallons. Next to alcohol, stearine is most to be recommended, on account of its great heating powers; and then train-oil, though the smoke and dirt produced by it in the tent are almost unbearable evils. Petroleum ought not to be employed, on account of its dangerous character and its being prejudicial to health. Wood and coals generate too little heat in proportion to their bulk. Parry was the first who, in his journey of 1827, employed spirits of wine; he still used wood and coals in 1820 and Lyon in 1822. 5. The nights are passed either in snow huts, or in tents. If tents be used, the climate must determine their material, whether cotton or sailcloth. A mackintosh floor-cloth should always be spread over the ground of the tent. It is indispensable to make the walls of the snow huts two or three feet high, in order to allow room for movement, and the closed side, _i.e._ the side opposite the entrance, must be made double, as it is always exposed to the direction of the wind. The tent entrance must be carefully closed with hooks and rings, and should not reach to the ground. A tent formed by two poles, about eight feet long, crossed at each end, with another to rest on these supports, is the most simple and secure form of erection. During the journey, a small sail may be advantageously used, whenever the wind is favourable; one of the tent-poles may be used as a mast, and an “Alpine stock” may serve as a yard for the sail. 6. The sledge party passes the night in a common sleeping bag, in which there may be, under propitious circumstances, smaller separate bags for each. When the temperature is not below -13° F., the sleeping bag may be made out of a warm strong quilt; but when the cold is more intense, it must be made of buffalo-skin, and to prevent its being pulled off during the night it should be buttoned at the top in the middle. Sheep-skins cannot be recommended for this purpose, as they are far heavier than buffalo-skins; and as they more easily collect moisture, so they freeze more quickly. The sleeping bag should always be wrapped up in the tent and packed with it on the sledge, so that it may come as little as possible in contact with the snow. If the temperature should fall below -35° F., the travelling party suffers greatly from the frost even in such a sleeping bag, and it would then be advisable to lay an inflated india-rubber mattress under the bag, so that only the legs of the sleepers should be exposed to the influence of the cold.