V. 



HERTFOEDSHIRE RAINFALL, PERCOLATION, AND 



EVAPORATION. 



By JoH.v HoPKixsoN, F.L.S., F.G.S., F.R.Met.Soc. 



Read at Watford, Utk March, 1896.* 

 PLATE I. 



Foe the last sixteen [now twenty] years I have made a special 

 study of the Meteorology of Hertfordshire, having taken meteoro- 

 logical observations in the county during that period (from 1876 

 to 1886 at Watford, and from 1887 to the present time at 

 St. Albans) in accordance with the regulations of the Koyal 

 Meteorological Society. For the years 1875 to 1879 and 1887 

 to 1891 I has-e collected records of the rainfall from all parts 

 of the county, the records for the years 1880 to 1886 having been 

 collected by 'the Rev. C. W. Harvey, F.R.Met.Soc. The general 

 results of the whole of these records, with tables showing the 

 monthly rainfall at all the stations, forming together a continuous 

 series of seventeen annual reports on the rainfall in Hertfordshire, 

 have been published in the ' Transactions of the Hertfordshire 

 Natural History Society.' 



The rainfall, percolation, and evaporation tables accompanying 

 this Statement, have been compiled by me from information com- 

 municated to me and to Mr. Harvey by the observers during the 

 last seventeen years, including several old records ; from returns 

 sent to me by observers at my request for this special inquiry ; 

 and from tables published in the ' Proceedings of the Institution 

 of Civil Engineers.' 



Rainfall. 



The rainfall tables (Tables I to XI) comprise every complete 

 record of rainfall in Hertfordshire for the last twenty years at 

 least, for which I have been able to obtain the monthly fall 

 of rain, with the mean for the half century ending 31st March, 

 1892. As I consider it desirable to give the summer and winter 

 rainfall separately, annual returns only have been of no use to me, 

 and this has somewhat restricted the number and in some cases 

 the length of the records, but I believe that the ten rainfall 

 stations are so situated that they represent the county as fairly 

 as such a small number could be expected to do, their records 

 giving an average annual rainfall slightly in excess of the true 

 average. 



In order to test their representative character I have deduced 



* Reprinted verbifim from the Appendices to the ' Report of the Royal 

 Commission on Metropolitan Water Supply,' 1893. 



VOL. IX. — PART II. 3 



