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valley". It foUo-n's tlio course of the Petham Valley, and used 

 to empty into a stream at Shalmesford Street, -wliich ran into 

 the river Stour, but of late years it lias boon turned into a small 

 pond at Perry Farm, where the earth is sufficiently porous to let 

 it drain away. The NaUbourne does not run at regular intervals 

 nor for any regidar time, but it generally begins about January, 

 after a wet autumn and winter, and runs till about the middle 

 or end of summer. In 18G0 it ran all tlxe summer, which was 

 very wet, and on through the winter and spring, but imtil re- 

 cently it was not known to have run for more than two years in 

 succession. The hiU from which the Nailbourne takes its riso 

 lies to the south and south east of the village, and is a spur of 

 the great chalk range which runs through Kent. The pond at 

 Petham is about 180 feet and the top of the hiU about 450 feet 

 above the sea level. The old theory of the origin of the Nail- 

 bourne was that in this hill there existed a great cavity ; that 

 after heavy rains this cavity became filled with water, which ran 

 out by a subterranean passage ; when the stream had once 

 started this passage was supposed to act the part of a syphon till 

 the cavity was empty. I do not place any faith in the old theory, 

 but I tliink that after heavy rains the water soaks down through 

 the soil and porous upj)er chalk till it meets with a much closer 

 and harder layer of chalk, through which water can pass but 

 very slowl}-. The chalk above this then gets supersaturated and 

 the water meeting with cracks and fissures, wliich act the part 

 of drains, follows them till they come to the surface of the hill 

 sides. It takes a long time for all the water to soak down 

 through the hills to this water-logged layer of chalk, and the 

 stream keeps running till all the water has di-aincd down. In 

 the report about the Canterbury AVater Works, the engineer 

 states that it probably takes a century for the rain which falls on 

 the hills about Cantei'biuy to reach the water-bearing stratum 

 which supplies the well, but I cannot believe that it takes quite 

 so long. After heavj- rains and before the Nailbourne breaks 

 out, the water in all the wells in the Petham Valley rises con- 

 siderabl}', and people who live in the vdlage can tell by the 

 length of i-ope they have to let out to reach the water when 

 the springs will rise in the pond. The rainfall before the Nail- 

 bourne last ran was — in October 2.370 inches, November G.130 

 inches, December 2.848, January 1.485 inches — total 12.833 

 inches ; and for the past season — October 3.510 inches, Novem- 

 ber 5.990 inches, December 2.G85 inches, January 3.060 inches 

 — total 15.155. Eather more than for the preceding season, so 

 it seems likely the Nailbourne will run about as strong as it did 

 last time, if the spring rainfall sliould be. about the same. The 

 above rainfall was taken at ]Uiltou Chapel, probably the rainfall 

 at Petham is rather higher, for in 1877 the rainfall at Milton, 



