CORRESPONDING SOCIETIES. 579 



Second Meeting of the Conference, September 1 1 . 



The Corresponding Societies Committee were represented by Mr. W. 

 Whitaker (Vice-Chairman), Rev. J. O. Bevan, Dr Horace T. Brown, Dr. 

 Garson, Mr. J. Hopkinson, and Mr. T. V. Holmes (Secretary). 



The Chairman briefly introduced Professor L. C Miall, who read the 

 following Address : — 



Dew-ponds. By Professor L. C. Miall, F.R.8. 



I lately undertook a new edition (the 83rd or 84th) of White's ' Natural 

 History of Selborne,' and found it necessary to consider the account of 

 the Hampshire dew-ponds which is to be found in Letter XXIX. tu 

 Barrington. ' We have,' he says, ' many such little round ponds in this 

 district, and one in particular on our sheep-down, three hundred feet 

 above my house, which, though never above three feet deep in the middle, 

 and not more than thirty feet in diameter, and containing perhaps not 

 more than two or three hundred hogsheads of water, yet is never known 

 to fail, though it affords drink for three hundred or four hundred sheep, 

 and for at least twenty head of large cattle beside.' This account, of 

 which I quote one sentence only, led me to inquire a little into this 

 curious subject by correspondence, by reference to the rather scanty 

 literature which already exists, and by personal visits. My inquiries 

 are, I must admit, very imperfect, but they may be the means of inducing 

 people whose opportunities are better than mine to collect fuller informa- 

 tion. 



White's account of the dew-ponds of Hampshire is largely confirmed 

 by more recent observation. A good description of such ponds is to be 

 found in a prize essay on ' Water Supply,' by the Rev. J. C. Clutterbuck. 

 He says that the tops of chalk hills, where no surface-water or springs 

 can furnish a supply, are often chosen as the sites of dew-ponds. 

 They ' are constructed by persons of experience and skill. At the spot 

 selected an excavation is made in the surface of the chalk, either round or 

 rectangular, from thirty to forty feet or more in diameter, from four to six 

 feet deep. The bottom, of a basin shape, is covered in portions with clay 

 carefully tempered,^ mixed with a considerable quantity of lime to prevent 

 the working of the earthworms.'-^ As the portions are finished they are 

 protected from the action of the sun and atmosphere by a covering of 

 straw. When the whole bottom of the pond is so covered with an efficient 

 and impermeable coating or puddle a layer of broken chalk is placed upon 

 it to prevent its injury by cattle or other means. Their cost varies from 

 30^. to 50^. When all is finished water is introduced by artificial means. 

 If there is a fall of snow this is collected and piled up in the pond as the 

 readiest and least expensive method of accomplishing the object. . . . Ponds 

 so constructed and filled have been known for periods of twenty or thirty 

 years never to become dry. The summer of 1864 was a notable exception.' 



Dew-ponds are often dug on the very ridge of a down, or else by 

 choice on the northern slope, which is the inland slope in most of the 



' Chalk-puddle is occasionally used instead, but is believed to be less efficient 

 and less durable. 



- It may be doubted whether the purpose of the lime is to prevent the working 

 of earthworms, which cannot live beneath a pond. It is an old practice to spread 

 wet clay with lime in the belief that it prevents slipping. 



P P 2 



