CORRESPONDING SOCIETIES. 585 



Wells, W. C. . . ' An Essay on Dew,' edited, with Annotations, by L. P. 



Casella, and an Appendix by R. Strachan. London, 



8vo. 1866. The original edition was published in 1818 



and reprinted in 1821. 

 Clutterbuck, Rev. J. C, . ' Prize Essay on Water Supply,' Journ. Roy. Agric. Soc, 



2nd ser. vol. i. pp. 271-87. 1865. 

 Field and Symons . . • Evaporation from the Surface of Water,' Brit. Assoc. 



Rep., 1869, Sect., pp. 25 and 26. 1869. 

 Lucas, J . . . ' Hydrogeology : one of the Developments of Modern 



Practical Geology,' Trans. Inst. Surveyors, vol. ix. pp. 



153-232. 1877. 

 Slade, H. P. . . ' A Short Practical Treatise on Dew-ponds,' London, 8vo. 



32 pp. numbered to 31 ; 3 folding plates. 1877. 

 Reid, Clement . . ' The Natural History of Isolated Ponds,' Trans. Norfolk 



and Norwich Naturalists' Society, vol. v. pp. 272-286. 



1892. 

 Brady, Professor G. S. . ' On the Nature and Origin of Freshwater Faunas,' 8vo. 



12 pp. No date or place. [1899.] 



The Chairman remarked that they would all unite' in thanking 

 Professor Miall for bringing before them the subject of dew-ponds in so 

 complete a form. He should like to have a little further information as 

 to the habit of sprinkling with lime with the object of keeping out earth- 

 worms. He wished also to know on what grounds Professor Miall said that 

 evaporation from the surface of dew-ponds was slight. His own impres- 

 sion was that evaporation would be somewhat rapid. Professor Miall 

 had spoken of the limited area within which dew-ponds existed. It was 

 singular that this limited area was one of low rainfall. Dew-ponds were 

 numerous in Berkshire, where they were made in the way described by 

 Professor Miall. While the Hertfordshire chalk was largely covered by 

 clay with flints, the Berkshire chalk was not. 



Mr. Clement Reid said that the question of the water supply in dew- 

 ponds was, like many other questions of water supply, much mixed up 

 with curious ancient superstitious observances analogous to the use of the 

 divining rod. He did not think that dew-ponds were formed in anything 

 like the scientific manner pretended by their makers. He had been 

 working during the last few years in a country where dew-ponds were 

 particularly abundant, and there had been several successive years of 

 severe drought. Nearly all the more recently made dew-ponds were dried 

 up, but a number of the older ones had not dried up. He did not think 

 that the older ponds were better made than the newer ones, but that a 

 process leading to the survival of the fittest was always gding on. When 

 a dew-pond dried up a new one became necessary. The farmers were 

 constantly making new ones, and sometimes, by accident, they got a satis- 

 factoiy site. It was an unfortunate thing that they were almost entirely 

 without meteorological observations on the high ground, where dew-ponds 

 abounded, our rainfall stations being almost invariably at a low level. 

 As to the question of dew or mist he did not feel qualified to speak. He 

 wondered whether it was possible that the film of scum constantly seen 

 on the surface of dew-ponds had any influence in protecting the water 

 from evaporation. Dew -ponds, being entirely isolated from running 

 water, were very important from a biological point of view. They could 

 watch the population of a pond becoming more numerous and varied, and 

 note how the higher animals and plants took the place of the lower which 

 first appeared. Dew-ponds and other isolated ponds would give much 

 valuable information as to the rate of dispersal of the aquatic fauna and 



