414 SECTIONAL TRANSACTIONS.—G. 
fifths of the fall occurs in the upper half of this stretch, the most of which also 
happens to form a part of the boundary between Canada and the United States, 
and along which, therefore, each country has equal rights in the use of the 
water. Below this, the river is wholly within Canadian territory. Fourteen- 
foot navigation by means of a system of canals and locks around the rapids has 
been available for many years. Power has also been developed to the extent of 
about 350,000 h.p., partly in connection with the canals, but mainly in a few 
plants, two of large size and recent installation, deriving their power by diverting 
for themselves a portion of the flow of the river. 
The paper refers to certain interesting and unusual characteristics of the 
river, the volume and variation of the flow under summer and winter conditions, 
and the action of ice in different forms, the last being generally the governing 
factor in determining the best method of developing power in the different 
reaches. It also describes the main features of certain projects recently put 
forward, either (a) for the primary purpose of power development on a scale 
necessitating the utilisation of the flow of the whole river, with provision for 
present and future navigation requirements, of (b) as a scheme for securing 
deep-draft navigation sufficient for ocean-going vessels, with the incidental 
creation of opportunities for power development. The second scheme is a part 
of a more extensive undertaking, to enable ocean shipping to reach the head 
of the Great Lakes system. From either point of view the projects are of 
exceptional magnitude and importance, the minimum ultimate depth proposed 
for the locks and navigation channels being 30 ft., and the total power when 
fully developed amounting to from 4,000,000 to 5 000,000 h.p., with individual 
plants having capacities of from 600,000 to 1,500,000 h.p. Considering that 
about four-fifths of this power is in Canada, within transmission distance of 
its largest industrial centres, mining areas, and its two largest cities, it is 
obviously one of the country’s most valuable assets. 
7. Joint Discussion with Section A on Optical Determination of Stress. 
Mr. A. L. Kimpaty.—Some recent Photoelastic Investigations by 
means of the Coker method in the United States of America. 
Monday, August 11. 
8, Profs. H. F. Moort and T. M. Jasper.—The Evidence for the 
Existence of an Endurance Limit in Metals. 
1. The importance of this problem. The study of fatigue phenomena and 
of various laws of fatigue failure are profoundly affected in their treatment 
by the existence or the non-existence of an endurance limit, This is an 
experimental problem. 
2. Brief historical summary. This would include the naming of Wéhler and 
his experimental work; Basquin and his proposed exponential relation; 
Stromeyer and the thermal evidence for endurance limit; and other people 
who have discussed the existence of such a limit. 
3. The elastic limit idea and its limitations. 
4. The inception of extensive investigations of fatigue limits in the United 
States. In at least two of these investigations the main problem laid out was 
the securing of direct evidence as to the existence of an endurance limit by 
means of long-time tests. 
5. A very brief summary of machines and test methods used, with reasons. 
6. The interpretation of test data of fatigue tests with respect to securing 
evidence for the existence of an endurance limit. 
7. Short-time tests for the fatigue limit and their reliability. 
8. Fatigue limits in non-ferrous metals. 
e Correlation between endurance limit and other physical properties of 
metals. 
9, Prof. C. F. Jenxry, C.B.E.—The Work of the Fatigue Panel of 
the Aeronautical Research Committee. 
Soon after the War the Aeronautical Research Committee appointed a panel 
to investigate fatigue in metals. This work has been carried on vigorously 
