706 PRACTICE OF AGRICULTURE. Part III. 



the temnination of the porous material, the drain need only be cut a little way into that, 

 as by boring through the rest a sufficient passage may be given to discharge the water. 

 In this way, the draining of such grounds as lie above or near to mines or pits may be 

 of great advantage. 



4274. Where a quarry or other jnt to be dried {Jig. 642. a) is situated above a porous 



stratum, whether 



642 ,.-/-' '"'V.'f'^Z^!^,,^^^^^^'^--'"'''''."-."- ^.'^- - ' '"'^r.B;*^ ^^ ^^^^ o^" gra- 



vel, it may some- 

 times be drained 

 by boring into 

 the latter (b). 

 In this way dif- 

 ,,;^p| ferent chalk pits 

 and lime quar- 

 ries have been 



drained in Kent and Hertfordshire. (See the Reports of these Counties.) In marl-pits 

 also, which, from the nature of their situation, mostly require much cutting througli some 

 part of their sides, in order to remove the water that prevents their being wrought, the 

 mode of letting the water down by means of pits dug through the upholding stratum 

 below the bed of marl into the porous materials underneath, might be economically 

 practised. In such cases, the number of the pits must be proportioned to the space 

 occupied by the marl ; and when they are required to be of such depths as to be liable 

 to give way, they should be built up, or nearly filled with loose stones, so as to admit the 

 water to pass off, such lateral drains as are necessary communicating with them. In 

 some situations of the pits, as where the bank slopes lower on the contrary side than the 

 level of the water, an easier mode may be practised ; such as by forming a drain in it, 

 and then perforating with a horizontal boring-instrument into the terminating part of the 

 stratum that holds the water ; thereby removing and keeping it below the level of the 

 marl. In addition to these, in some cases, as where the water of such pits proceeds from 

 springs in the high grounds above them, it may be useful to intercept and convey it away 

 before it reaches the marl-pits. 



4275. The drainage or drying xip of lakes or ponds comes occasionally within the 

 practice of the drainer, especially in countries with an irregular surface. There are, 

 perhaps, few natural lakes indeed, the surface of the water of which might not be very 

 considerably lowered, by deepening their natural outlets, the consequence of which would 

 be, in many cases, a very considerable accession of generally rich land round their mar- 

 gins, a better drainage for the surrounding country, and an improved climate. Mucli, 

 it is said, might be done in this way in Ireland; but there can be" no doubt that in every 

 country in the world a great deal may be done. In flat countries nearly on a level v/ith 

 the sea, like Holland and parts of the counties of Cambridge and Huntingdon, the 

 water will in general require to be raised by machinery ; but in by far the greater number 

 of cases, deepening the natural outlet will be found amply sufficient. 



4276. Bar Loch, in the county of Renfrew, was reduced in size by drainage and embanking, in 1814, at 

 an expense of nearly 10,000/., which has since returned 13 per cent, per annum ; 280 acres have been laid 

 dry upwards of 200 of which have been since under crop. A very interesting account of this drainage 

 will be found in the Highland Society's Transactions, Vol. vii. p. 375. 



4277. Steam-engines have lately been employed, both in Cambridgeshire and Lincolnshire, as substitutes 

 for the very uncertain power of wind, to raise the water from the low lands, and deliver it into the drains 

 and rivers by means of scoop wheels working like a grinding-stone in its trough. Wheat and other corns 

 have thus been sown on lands never before ploughed. The improvement indeed is one of the greatest 

 that has taken place in fenny countries, since they were first attempted to be drained and embanked. 

 {Mech. Mag. vol. v. p. 179. and Gaid. Mag. vols. iv. and v.) 



Sect. VII. Formation of Drains, and Materials used infilling them. 



4278. Drains sliould be formed with as mtich truth and exactness as possible : such 

 labourers as are not dexterous in using their tools seldom make them well. The most 

 general method of performing this sort of work is by admeasurement, at so much a rod, 

 or a score of rods, wliich necessarily induces the workmen to do as much as they possibly 

 can : they should, therefore, be frequently inspected, to see that they keep to the proper 

 and required depth, that the earth taken out be laid in such a manner as not to fall down 

 again into the drains in time of filling them, and that the surface mould be kept on one 

 side free from the clayey or other material of the inferior stratum. 



4279. When there is any declivity in the ground, drains should be made in a slanting 

 direction across it, instead of the old method of conducting them according to the nature 

 or inclination of the slope. By attending to the former mode of cutting the drains, the 

 wetness is not only more effectually removed, but, by allowing the water to pass away 

 in an easy current, they are rendered less liable to be choked, or, as it is frequently 

 termed, blown up, by which artificial oozings of water are sometimes formed in sucli 

 places. But where grounds are either quite or nearly level, it has long been a general 

 practice to cut the drains at the different distances of about sixteen, twenty-four, and 



