RAINFALL IN nEUTFORDSniRE IN 1881, 65 



have been underrated. Mr. Symons, in the ' Meteorological Maga- 

 zine ' for February, gives tlie average depth of snow in Herts at 

 about 7 or 8 inches ; in this particiihir instance it is estimated that 

 this would represent '70 to '80 of snow-water, almost the whole 

 monthly return of some observers ; the amount found in the gauge 

 has possibly misled them, for that amount was probably but a little 

 of the whole, the rest having been blown out by the gale, before 

 which the snow drifted. The snow in my own Snowdon gauge 

 only yielded -IB, manifestly too little. Others again may have 

 been misled by following the ordinary rule, and taking the depth 

 of 1 foot of snow to equal 1 inch of water, whereas owing to the 

 peculiar fineness of the snow, which caused it to lie more compact, 

 experiment showed that only 10 inches of snow yielded 1 inch of 

 water. On the other hand, the December fall was much in excess, 

 principally in consequence of the very heavy fall of the 1 7th (in my 

 own case the heaviest since Aug. 1879) ; a fall which was general 

 throughout the county, and which caused considerable floods. 



The mean monthly fall for 1881 differed from the mean monthly 

 fall for 1870-79 by the following amounts : — 



January — 1-19 July — '64 



February -f-1-38 Auijust -1-2 -47 



March -j- -29 September — '38 



AprQ —1-40 October -\- -09 



May — -87 November -\- -05 



June — -49 December -i-r72 



Distribution of the Rainfall throughout the County. — While the 

 rainfall in the Thames basin, i.e. that part of the county drained 

 by the Colne and the Lea, was ahove the mean for the district ; the 

 fall in the basin of the Ouse, i.e. the extreme N.W. part of the 

 county drained by the Ivel and Cam, was hdow \kiQ mean. On 

 the one hand the fall at Moor Park, Gorhambury, and Great Gad- 

 desden was large, while on the other hand the fall at Odsey was 

 remarkably small, which may in some measure account for the 

 difference. The amounts gauged at Great Gaddesclen during August 

 and September will no doubt attract attention. Mr. Drake, how- 

 ever, assures me that to the best of his belief these figures are 

 correct (between 10th of Aug. and 9th of Sept. the gauge was 

 emptied by a deputy). I have therefore taken these values into 

 the account. It may be mentioned as a piece of corroborative 

 evidence that at this station during August and September, morning 

 after morning the water had to be baled out of a tub outside the 

 greenhouse to prevent it from overflowing. 



In the eleven minor river-districts, which, of the seventeen into 

 which the county is divided, are the only ones at present with 

 observers, the mean fall was as follows : — 



Lower Lea 29-46 ( Lower Colne 30-90 



Upper Lea 26-72 Colne Ver 31-26 



-^ I Mimram 27-57 ( Gade 32-47 



^^^'^ 29-26 i^gi jji^ 25-27 



^'° i^'Yi Cam llhee 22-38 



Ash 29-10 



VOL. II. — PAllT II. 5 



