On Agricultural Mechanics. J08 



bore or tunnel through the soil at the depth of 18 or 20 inches, 

 without removing the surface, is another of these attempts, but is 

 by no means so good a one. It is only in those soils in which 

 such a bore will stand, and not fill up, that this machine can be 

 used, and then the mode of its action necessarily hardens and 

 condenses the clay through which it passes, making it dense and 

 impervious around the pipe which it leaves behind it. 



The machine consists of a block of wood or piece of iron of a 

 sugar-loaf form, attached by one or sometimes two narrow but 

 strong uprights, about 2 feet long, to a strong framework of wood, 

 to which the draught-chains are fixed. It is drawn either by a 

 strong force of horses, or by a windlass and chain, which is moved 

 from drain to drain as each is completed. The two uprights 

 necessarily cut through the land above the drain, and so far con- 

 nects it with the open air ; but as they are narrow, the passage 

 formed by them fills up, the sides collapsing as the machine 

 passes. 



A series of parallel drains is thus formed at a depth of 

 18 inches. These are connected with a master-drain, dug with 

 the spade, into which the water from them runs and finds an 

 outlet from the field : when this is filled in, the drainage is com- 

 plete. Its permanency and efficiency of course depend on the 

 nature of the soil and the subsoil it passes through. Under the 

 most advantageous circumstances, however, it does not last long. 

 This implement has been long in use, it is referred to in many of 

 the county surveys of 1813. The use of the capstan also to 

 draw it along, instead of employing a great number of horses, was 

 then frequent. 



A better way of draining, however, is that called clay-draining. 

 A trench 20 inches deep, 2 inches wide at bottom, and 10 inches 

 wide at top, is cut with long narrow spades, which do not require 

 the men using them to descend into the trench. After the trench has 

 been dug a wooden mandril is made use of. It is formed of pieces 

 of wood 6 inches deep, 2 inches wide at bottom, 4 inches wide at 

 top, and from 9 to 12 inches long, hinged together so as to give 

 the whole chain flexibility, and fits the bottom of the ditch to a 

 height of 6 inches. The clay of the subsoil is placed above it, 

 and being wetted, is hammered down above it, and the rest of the 

 soil is then thrown in. The mandril is then drawn along by 

 means of a long pole pointed at one end, to which it is attached 

 by a chain near the pointed end : this pole is made to act as a 

 lever. (See figure.) On being drawn along, more earth is thrown 

 in and hammered down above it, and so the work proceeds. This 

 is more durable than the work performed by the mole-plough. 

 It costs about I4d. per chain. Neither of these modes of drain- 

 ing, it is evident, admits of the action of the subsoil-plough above 



