102 



Geology of the Keythorpe Estate. 



and submains, all 4 feet deep, 987 yards, equal to 179 perches, 

 or say, 51 perches to the acre. 



In Over Hammer, then, we have 69 perches, and in No. 39, 

 51 perches ; average of the two, 60 perches to the acre. 



With equidistant drains laid along the fall of the ground at 

 intervals of 8 yards, we should have, as stated above, 114 

 perches ; on the average of the Keythorpe system, 60 perches ; 

 saving by the Keythorpe system 54 perches, containing 891 

 pipes, of a foot long. 



On the equidistant system and 10-yard intervals there would 

 be 92 perches ; and deducting the average of the Keythorpe 

 system, we have 32 perches of drain saved by it, containing 528 

 pipes. 



Those who would calculate the sum to be saved by draining 

 an estate on the Keythorpe system, have only to apply the above 

 data to the customary local prices of labour and materials in their 

 respective districts. The following may be taken as illustrations 

 of some of these local variations : — 



Two farms were drained on the London clay by an eminent 

 and experienced drainer. The depth of the drains was 4^ feet, 

 that of the submains 5 feet, width of interval 8 to 10 yards. 

 Fr6m what I saw of the soil and subsoil, and the irregularities 

 at their junction while the drains were being dug, I have no 

 doubt that the Keythorpe system would have applied to the case. 

 For the drains li-inch cylindrical pipes were used, unless the 

 length of drain exceeded 10 chains without joining a submain, 

 when the bore was increased to li inch, both collared. For the 

 mains and submains, pipes of 3-inch bore were used without 

 collars : the cost of these, to be delivered on the land — the num- 

 ber to be determined by measurement of the drains, all flawed 

 pipes being rejected — was, for Ij-inch pipes, 25^. the thousand ; 

 for li-inch, 285. ; for 3-inch, 35^. The average prices for dig- 

 ging drains were, — for mains and submains, 5 feet deep. Is. the 

 statute perch. The parallel drains averaged ^d. the perch in 

 winter, and 9c?. in summer, for the draining operations were car- 

 ried on through the summer, which was also the Keythorpe 

 practice. If we suppose half the drains to have been at 8 yards, 

 and half at 10 yards (but there were more of the former than of 

 the latter), the following would have been the saving by the 

 Kejrthorpe system : — At 8-yard intervals there would have been 

 114 perches of drains and submains ; at lO-yard intervals, 92 

 perches to the acre ; average, 103. The average of the Key- 

 thorpe system is 60 perches to the acre — the difference in its 

 favour 43 perches, containing 709 pipes. The total saving in 

 money would then be — 



