36 
Flow from The Author has had the quantity of water flowing out 
Oxted Tunnel ; ; 
ganged. of the Oxted Tunnel regularly gauged during the last 
24 years, and has found the largest quantity that during 
that period has flowed away was during the present 
year, when on the 19th February 326:03 cubic feet 
per minute flowed away from the Croydon area. ‘The 
previous largest quantity was 248°8 cubic feet per 
minute on 20th February, 1883. The quantity of 
water flowing from the Oxted Tunnel does diminish the 
volume of the Croydon Bourne, and may prevent 
some small flows from taking place. 
Copeings of This 1866 Bourne flow was gauged by the Author on 
many occasions for the information of Croydon Authori- 
ties, and especially their Chairman, the late Mr. C. W. 
Johnson, F.R.S., who took great interest in such 
matters. When this Bourne was at its highest point of 
flow, on the 27th February, 1866, the quantity flowing 
into the Bourne culvert at the ‘‘ Windsor Castle,” 
Brighton Road, which was then the upper end of the 
culvert which had been constructed for the diversion 
and the prevention of flooding by the Bourne of the 
lower parts of Croydon, and for lowering the level of 
the water line under the Old Town of Croydon, was at 
the rate of 1,800 cubic feet per minute, and the volume 
flowing out of the mouth of the Bourne culvert into the 
Wandle on the same day was 3,212 cubic feet per minute, 
this being the largest flow of the Bourne of which there 
is any record. 
Gaugings of In the year 1873 there was another Bourne flow at 
1873 Bourne. 
Croydon, and the volume of this flow was gauged by 
Mr. Thomas Walker, the town surveyor of Croydon, 
and the quantity of water flowing into the Bourne cul- 
vert at the ‘‘ Windsor Castle,” on the 17th February, 
1873, was 228 cubic feet per minute, and out of the 
