INLAND WATER SURVEY 375 
from a gauge lent by the Office. With these few exceptions the Organization 
relies for its data on returns made voluntarily by persons who have purchased 
instruments themselves. 
In general, daily readings of rainfall are furnished by all observers, but 
for many stations in remote parts of mountains or moors only the monthly 
total is available. All stations in categories (1) and (2) and selected stations 
in other categories forward monthly reports of daily rainfall, for use in 
drawing the rainfall map published in the Monthly Weather Report. At 
the present time the number of stations reporting monthly is about 1,400. 
For about 600 of these stations the monthly total is printed either in the 
Monthly: Weather Report or the Meteorological Magazine, and for a large 
proportion of these the percentage of or difference from average is also 
given. The remaining stations render an annual return only. 
Most stations in category (1) and a few in other categories, maintain 
recording gauges, from the records of which data in regard to rainfall 
duration and the intensity in heavy falls are evaluated. Eighty-one such 
records were available in 1931. 
LocaL RAINFALL ORGANISATIONS. 
In many parts of the kingdom local interest in rainfall is fostered by 
organisations, often forming. a part of a local scientific society, which collect 
observations from their correspondents and publish the readings in various 
forms, usually in the newspaper Press. These organisations have no 
official status, but they represent some approach to a regional system of 
dealing with rainfall data. They vary much in regard to the scale of their 
activities, At one end of the scale we have an organisation in Ayrshire 
under the control of Mr. W. Dunbar of Kilmarnock, who publishes shortly 
after the close of each month a duplicated report containing readings for 
100 stations, together with a map showing the distribution of rainfall over 
the area. At the other end of the scale would be a small group of observers 
sending in records once a month to a secretary for insertion in the local 
paper. In some cases it is found possible to utilise the services of the local 
organiser to deal with questions of the exposure of gauges and reliability 
of readings, but such services are not utilised in any general or systematic 
way. A list of local organisations known to the British Rainfall 
Organization is appended :— 
Hertfordshire Natural History Society and Field Club (Mr. C. P. Sinclair). 
Northamptonshire Natural History Society (Mr. R. H. Primavesi). 
Norfolk Rainfall Organisation (Col. H. C. Copeman). 
Barnstaple Atheneum (Miss Young), 
Mid-Wessex Rainfall Association (Rev. F. P. Synge). 
Cornwall Rainfall Association (Mr. A. P. Jenkin). 
Manchester and Stockport Rainfall Organisation (Mr. A. A. Barnes). 
Irish Rainfall Association (Mr. E. W. M. Murphy). 
Mr. A. J. Jenkins of Jersey, Miss Cordelia Marshall of Ambleside, and 
Mr. W. Dunbar of Kilmarnock also collect rainfall statistics regularly. 
EXTRACTION, CHARTING AND PUBLICATION OF Data. 
Monthly and annual totals for nearly all stations are plotted on maps, 
from which the charts of rainfall distribution published in British Rainfall 
on a greatly reduced scale are drawn. Maps are also prepared showing 
the annua] number of ‘ rain-days’ and ‘ wet-days.’ The monthly and 
annual total fall for every station is entered on a ‘ ten-year sheet.’ Stations 
