53 
Those three Tables being arranged according to the system 
of M. Bexeranp, dividing the year into two equal portions, 
namely, the hot or Summer season, extending from 1st May to 
the end of October, and the cold (Winter) season, comprising 
the other six months. Also extracts from the Rev. T. A. 
Preston’s returns, being the annual rainfall at New Swindon 
between 1874 and 1884 inclusive, (Table No. 4, see page 61.) 
The drainage area of the various streams is exhibited on the 
_ Map, (Drawing No. 1) and may be stated as follows :— 
TRIBUTARIES OF THE RIVER THAMES ABOVE LECHLADE, 
WITH THEIR RESPECTIVE DRAINAGE AREAS. 
hd partially | Im ble} Drai 
an aria. permeabie rainage 
NAME Ueeeeagie, Ground ene 
Ground 
River Churn tos it fee ...| 40 sq. miles | 15 sq. miles | 55 sq. miles 
un  Coln we ..| 47 do. 16 do. 63. do. 
Ampney and Mar ston Brooks ... 28 = do. 10 do. 38 ~— do. 
Thames Proper. Streams flowing S. E. ) 
& E., being the Ewen, &c., ;| 30 do. 27.25 do. 57.25 do. 
and the Swill Brook ' 
" Streams flowing N.&N.E,, 
being the rivers Ray, Shire 
Ditch, Bide Mill Brook & (| 39-75 do. 70 do. {109.75 do. 
Cole.. Ais 
Total ... ...|184.75 do. 138.25 do. 323 ~— do. 
River Frome, to Downton and Stone- 
house Mills es Or Feat 65 do. 14 do, 79 do. 
un  Chelt ree ade bate Sas ido: 2 do. 3 = do. 
_ First, as regards the flow of the Thames at Lechlade, 
resulting from the gathering ground, of which the area as 
stated is 323 square miles, it will be convenient to take some 
_ known standard, with the view to comparison, say so many 
cubic feet flow per minute for each square mile of drainage 
area. I do notthink that I can take a better than one from the 
river Thames itself above tidal influence, as flowing over 
Teddington weir. The drainage area above this has been 
_ definitely ascertained to be 3,676 sq. miles, and the dry weather 
flow 12 cubic feet, or 75 gallons per minute for each sq. mile, 
whilst the maximum flow in periods of excessive flood may be 
approximately stated at thirty times as much. 
