Engineering Wonders of the World
Volume III

292 ENGINEERING WONDERS OF THE WORLD. A HEATH PLOUGH BREAKING LAND FOR AFFORESTATION. the behaviour of a Fowler trenching plough in an area of suburban land broken up for tree planting :—“ The ploughing of this land pre- sents considerable difficulty, as at about the middle of the land in question there is a vein of bog iron-ore running from east to west. In the southern part, with its light, sandy soil, the plough makes its deep Ve£ ^ard furrow without difficulty, but in the middle the steel shares begin to creak and groan. The plough only moves forward by fits and starts. But the engine power conquers the elementary power of the ore veins. The stones break with a crash, and are slowly but surely forced out of the upper edge of the furrow by the mould board. Colossi of from 1,100 to 1,650 lbs. weight are then thrown up like mere sods. Only engines of powerful build and solid con- struction can perform such a task. The trench is made quite smoothly, and the whole work proceeds so noiselessly that the humming and puffing of the working engine can scarcely be heard.” By means of the same, or a somewhat similar machine, marshy land may be drained and rendered fit for cultivation. About ten years ago an Algerian swamp, once a favour- ite resort of sportsmen, and also a source Drainage of Swamps. of malarial fever, was thus converted into vineyards or corn land. The task of effecting the drainage was extremely difficult, as the ploughs sank repeatedly into quagmires, and special causeways had to be constructed to bear the engines ; but eventually the land was deprived of its surplus moisture, and, by a succession of operations, made to produce fine crops of grapes and corn. It is certain that such work could not have been carried out by hand labour, except at a cost which would have deterred any one but a wealthy philanthropist from undertaking the enter- prise. A particularly ingenious drainage machine, known as a “ mole drainer,” is used in a strong clay subsoil M°le , Drainer. naturally impervious to water. The drain is cut by a vertical share carrying at its lower end a cylindrical body pointed off A TRENCHING MACHINE. One of these will make trenches up to 2 feet in depth and up to 3 feet in width. (Photo, Messrs. John Fowler and Company.)