
May 5, 1923] 
NATURE 
607 

Water-Power in the British Empire.! 
By THEODORE STEVENS. 
bs Bee Water - Power Committee of the Conjoint 
Board of Scientific Societies in its various reports 
has ably summarised the information on water-power 
available throughout the British Empire, and the Board 
of Trade Water-Power Resource Committee and Sub- 
Committee have dealt with the British Isles in a 
similar way. Canada has done more measuring of 
those resources than any other part of the Empire. 
Canadian water-powers in service, catalogued in 
Water Resources Paper Number 27, numbered, in 

There have been, within the last twenty years, water- 
plants installed in twenty different places, in every one 
of which after the capital was spent there was a rude 
awakening to the fact that the quantity of water neces- 
sary for the work undertaken was not available. A 
total of 25,000,000]. has been spent in those twenty 
places, and has proved financially unprofitable. Much 
more capital has elsewhere been profitably invested. 
Many other water-powers have proved successful. 
Enough has been said to show that reasonable caution 

| PAovo by Cot. Sir Ho A. Van Ryneveld, KBE, 
Fic. 1.—Victoria Falls, Rhodesia ; view from the air, 
The river at the fall is 1 mile wide and drops into a narrow gorge 400 feet deep. 
The large model of Victoria Falls in the Imperial Institute, South Kensington, London, aids one to visualise this configuration. 
1920, 336 developed water-powers. Of these the 
summary, arranged by me under the diferent heights 
of falls, shows 
43 were working with heads of water between 5 and ro reet; 
47 at heads between 11 and 15 feet ; 
ee - ee. 30- ,, 
84 ” ” ” 31 ” 7o ” 
With these figures before us, development of any 
head of water that may be available can be justified 
from past experience; but it is a great mistake to 
conclude that sufficient power can be developed from 
a stream until all the details of the problem have been 
fully studied. 
* Substance of two lectures delivered at the Royal Institution on March 
1 and 8, when illustrations of the important waterfalls in each part of the 
Empire were shown. 
NO. 2792, VOL. 111] 
necessitates efficient preliminary study before capital 
is invested. 
Another note of caution refers to the distance that 
it is economical to transmit power. For example, it 
would not pay to generate hydro-electric power to 
supply a lighting load 75 to roo miles away, if there is 
a coal-mine near the consumers’ end of the transmission 
line; nor is it practicable to undertake to supply 
separate villages and farms on the line of a high-voltage 
transmission, because it costs many thousands of 
pounds to tap power from a high-voltage line, and the 
small consumption in village and farm cannot possibly 
pay the interest on this expenditure. It would be un- 
necessary to make such comments if this uneconomi- 
cal arrangement had not been seriously advised by 
