46 



On Draining. 



the joint action of drains and superficial evaporation. These fissures seem 

 to stand in the stead of porosity in such soils, and serve to conduct water 

 to drains rapidly, after it has trickled through the worked bed. It is pos- 

 sible, too, that in deeply-drained clays of certain texture the fissures may 

 be wider, or more numerous, in consequence of the contraction of a greater 

 bulk of earth than when such soil is drained to a less depth. However this 

 may be, it is asserted by several respectable and intelligent farmers in 

 Kent, who have laid drains very deeply in clay and stiff soils, that the flow 

 from the deepest drains invariably commences and ceases sooner than from 

 shallower drains after rain." — vol. v. p. 155. 



To give efficiency, therefore, to a system of deep drains beneath 

 a stiff clay, these natural channels are required. To produce 

 them there must be a continued action of heat and evaporation. 

 If this action should be defective or uncertain, can the system be 

 efficient in that form ? and, finally, is any such action always to 

 be expected ? 



Perhaps, without looking diligently into the statistics of this 

 subject, most people are little aware of the extent of variation to 

 which our English climate is liable. I invite the attention of my 

 readers to a short consideration of it, as affecting the particular 

 question now before us. 



In the last Number but one of the Society's Journal was an essay 

 of more than common merit, " On the Climate of the British Islands, 

 and its Effect on Cultivation." Its writer, Mr. Whitley, of Truro, 

 tells us (p. 7) J that It appears that the eastern counties, and the 

 midland counties around Bedfordshire, have, as a whole, the high- 

 est summer temperature in England." Let us, then, to place the 

 matter in a strong light before us, compare, as nearly as our 

 means of information will permit, the climate of those portions of 

 the kingdom with that of this district on the verge of the York- 

 shire hills. 



Mr. Whitley gives in the same essay a table, Showing the 

 Mean Temperature of each Month of Summer, and of the whole 

 Year, at the Places therein mentioned." In this table the afore- 

 said particulars for Bedford are contained. There is no place, 

 indeed, which is so situated as precisely to represent the other 

 member of the comparison. Those offering the nearest approxi- 

 mation are Ackworth and Derby ; but the former, lying about 

 fifteen miles due east, well removed from the influence of the 

 hills, and on the edge of the magnesian limestone, though some- 

 what nearer than the latter in respect of distance, has fewer points 

 of essential resemblance. Derby, on the other hand, seated 

 about 40 miles to the southward, upon the vast sandstone tract 

 of central England, and not very far from the eastern base of the 

 great elevated range to which we have before alluded, presents a 

 general aspect analogous in many points to that of our own case. 

 Its more southern latitude and greatly lower level of course im- 



