SAVING AND USING THE EAIN. 
153 
might mention that in the flood of November, 1894, the discharge of 
ithe Thames over Teddmgton Weir amounted to 20,185,700,000 galls, 
in one day (November 18). The average daily discharge is but 
1,802,581,288 galls., or only one-fifteenth of the amount quoted; 
and allowing 17 galls, to equal a cubic yard, the excess of water on 
that day would have been sufhcient to cover to a depth of 3 feet an 
Area of 228,161 acres, or 356^ square miles. He had been interested to 
hear what the Chairman had said as to the effect of covering his 
percolation gauge with turf, because there could be no doubt that this 
was to give the gauge a much closer approximation to the conditions 
generally found in nature than when the surface is kept bare. The 
amount of moisture taken up by the vegetation for its own use, and the 
difference in the amount of evaporation into the air caused, directly and 
indirectly, by its presence, greatly affected the quantity of water which 
was available to be passed to the lower strata of the ground. During the 
warmer half of the year, in ordinary seasons, this was, he believed, 
practically nil ; and in the colder half he did not think it could be safely 
.assumed, from the Rothamsted percolation gauge observations, where the 
surfaces are kept bare of vegetation, to amount to so much as one 
half. But taking the year through it was certainly incorrect to assume 
ithat anything like one half of the total rainfall found its way to the 
•deeper springs ; possibly on an average the amount approached to one- 
fourth of the rainfall, but this he considered to be quite an outside 
^estimate. The lecturer had dealt with his subject in a very practical 
manner, and this fact had greatly enhanced its value ; for when it could 
be shown that a system could effect so substantial an advantage as the 
saving of no less than £600 per annum little more was needed to 
demonstrate its advantages. 
Mr. W. Marriott said that the paper ended with a very practical 
suggestion. There was no doubt that a great deal of saving could be 
accomplished by utilising the rain water which falls on the roofs of 
buildings, greenhouses, &c. The late Mr. G. J. Symons, whose work 
had been referred to by the author, published his first volume of 
British Rainfall " for the year 1860, and these volumes had been con- 
•tinued annually up to the present time. There had been a deficiency of 
xainfall during the last few summers. It was therefore unsafe to base 
^conclusions upon these results. Observations, to be of much value, 
should extend over a considerable number of years. Mr. Symons's works 
had put us in possession of valuable data from which we could make 
-definite conclusions. 
Mr. E. Mawxey said that it might not be generally known that this 
■question of the storage of rain water had at one time engaged the atten- 
tion of the late Mr. Shirley Hibberd, who in 1879 issued a pamphlet 
entitled "Water for Nothing — Every House its own Water Supply." 
In the same year Mr. Sowerby Wallis, now at the head of the Rainfall 
Organisat on referred to by Mr. Kay and also by Mr. Marriott, read a 
paper betore the Croydon Congress of the Sanitary Institute on Rain 
•collected from Roofs." 
Mr. Kay replied : " As I stated in my paper, I had no idea of pro- 
mulgating any new theory, but to call attention to the immense volume 
