In addition to these perils the natives are often unfriendly, and there have been many instances of cruelty and murder. In these districts it is, of course, impossible to use wagons or any large vehicles, and the climate is unhealthy for horses and cattle. Negroes, therefore, act as carriers and march along the narrow paths with heavy loads on their heads. These natives are very strong, and may be seen carrying large bales, boxes, and even bicycles through the jungle. The Europeans of the party either walk too, or are carried in hammocks slung on poles. An awning is fixed over the hammock, and the occupant can lie down comfortably while he is borne along by two or more negro porters. Wounded men or those ill with fever are often taken for many miles in this fashion, and in Nigeria special hospital hammocks are provided for this purpose on which the familiar red cross may be seen. [Illustration: MONO-RAIL WORKED BY NATIVES.] The natives of these tropical forests either carry their merchandise and other burdens themselves, or have light conveyances suited to the narrow tracks that are the only roads of the country. The Sobo negroes of West Africa have a very ingenious arrangement, and often three or four of them may be seen walking in single file and carrying a long pole on their shoulders. From this pole are hung jars, bundles, and baskets of fruit and vegetables. In another district a still more curious device is used. This is a single railway line running between two towns, on which light trucks can travel. These trucks have two wheels each, one behind the other, and to each truck is fastened a pole which projects on the left-hand side. Negroes walk beside the line, holding the poles and thus driving the cars along. In regions where the forest is less dense and the climate more dry and healthy, animals can be used, and sometimes strange teams are seen--camels, donkeys, and oxen being all pressed into the transport service. CHAPTER IX THROUGH ICE AND SNOW In the Arctic regions, far beyond the reach of railways, and where even the sea is frozen during many months of the year, we find strange conveyances and means of travel, for in those desolate lands there are no roads. Even if a track is made it may, within a few hours, be covered with drifting snow and entirely lost. Horses and oxen cannot live in the bitter climate of the north, so carriages, or any other wheeled conveyances, are useless. Travellers, therefore, must needs adapt themselves to the conditions of weather and country, and either invent new means of locomotion or else borrow ideas from the original inhabitants of those bleak, snow-clad lands. The first Arctic explorers described their experiences in the Polar regions, and life among the Esquimaux has changed very little since those pioneer days when Frobisher and Sir Humphrey Gilbert set sail in search of a new route to India and the East.