INTRODUCTION. XXV 



g'enerally within the Middlesex boundary. From West Drayton it 

 is carried east to Norwood (crossing the Cran north of Cranford), and 

 joins the Brent below Hanwell. The level of the canal falls 114 feet 

 from Rickmansworth to the Thames. The PadcUngton Canal (opened . 

 1801) connects the Grand Junction with the metropolis. It leaves 

 it at Bull Bridge, near where it crosses the Cran, and passes Northolt, 

 Apperton, Twyford, and Kensal Green. It is on the same level 

 throughout. The JRegent's Canal (opened 1820) continues the system 

 from Paddington entirely round the north of London to the Thames 

 at Limehouse. It passes through two tunnels, one under Maida 

 Hill, the other under Islington and the New River. It is nine miles 

 long, with twelve locks and a fail of eighty-four feet. 



The Kensington Canal (opened 1828), three-quarters of a mile long, 

 runs from Chelsea meadows to Kensington. 



8. Soil and Agrictjltuke. — In few counties, says Mr. Clutterbuck, 

 is the meadow and arable land so nearly divided, or the extent so 

 clearly defined ; and, though not without exceptions, the surface occu- 

 pied by the London clay and the valley drifts respectively, determines 

 the extent under grass and under the plough * {Jour. Roy. Agr. Sac, 

 second series, vol. v. p. 9). The part of the county in which the 

 London clay is at or near the surface, consists of gently rising hills 

 with small valleys gradually worn away by the surface drainage. This 

 is sufficiently rapid to prevent serious stagnation from the absence 

 of subsoil drainage. Mr. Clutterbuck states that in the farms on 

 the clay all operations are made subservient to hay-making for the 

 London market. ' Very many of the fields are laid out in small and 

 not very convenient enclosures, sometimes overgrown with timber 

 in the hedgerows, which are generally of white or black thorn. The 

 elm timber is often unduly shredded, and the oaks, especially on the 

 sheer London clay, are of stunted growth. As a rule, the higher 

 ground, or that on the outcrop of the plastic clay, is best clothed with 

 timber.' {Ibid. p. 10.) 



Mr. Caird speaks of the land in the neighbourhood of Wilsdon, 

 about five miles south-east of Harrow, as exceedingly stiff and 

 undrained. ^The tenants do not seem anxious to have their land 

 thoroughly underdrained, and yet it is so wet that they cannot put 

 stock on it after October. During an open winter the fields have a 

 pleasant green appearance, looking richer than they really are, their 

 summer produce being only one and a half to two loads of hay per 



* According to the Agricultural Returns for 1808, of 108,956 acres, the total acreage 

 under cultivation, 75,006 acres, or more than two-thirds, are under grass. 



