PRESIDENTIAL ADDRESS. 29 
particularly nice system—I travelled in the cars on the 
occasion of my last visit to the continent of Hurope. I saw 
something of the Lartigue method, and I had the oppor- 
tunity of meeting the celebrated Mr. Behr, and listening 
to the description of the system by the author himself, 
This system, which was advocated for the Liverpool — Man- 
chester high speed route by some of the highest authorities 
in the scientific world, did not receive the support of the 
public. But while Mr. Behr’s train requires an expensive 
structure to run upon, the centre of gravity of which for 
the purposes of stability lies below the line of support, Mr. 
Brennan is able to content himself with a mere rope on the 
top of which his machine supports itself in the air, appar- 
ently disregarding the principles of gravity, so much so 
that if you put a weight on one side or try to pull it over 
it moves over in the opposite direction, and so gets its 
balance restored. The principle involved is that of the 
gyroscope or gyrostat as Mr. Brennan calls the pair of 
apparatus, which are kept revolving at a high velocity on 
the car. It remains to be seen of what practical use the 
invention turns out to be, but its simplicity and ease of 
application would seem to insure for it a great future. 
It is sometimes said that one learns more from failures 
than from successes. Let us hope at any rate that the 
one or two terrible events, for which the past twelve 
months will be noted, will result in ultimate benefit. I 
refer in the first place to the Quebec Bridge disaster, the 
report on which has recently appeared. The disaster should 
certainly put a stop to the tendency to allow higher and 
higher strains on known materials, and it should be a 
reminder that the strains on compound structures are not 
always easily determined, and that it devolves on the 
engineer to see that his joints and connections are 
thoroughly well designed and the stresses on the members 
