G.—ENGINEERING. 123 
everybody is well aware. But for myself it carries this lesson, that in 
speaking from the Chair of the Engineering Section I am now, so to say, 
broadcasting to a multitude of intelligent amateurs. I hope the experts 
will forgive me if in what I say they find nothing that is not already 
familiar. I shall try to speak plainly to the plain man. People who have 
a preference for the unintelligible will, no doubt, be able to gratify it in 
at least one other Section. 
What has mechanised the world is, more than anything else, the pro- 
duction and the distribution of power. To-day we are concerned with the 
best ways of converting the heat of combustion of fuel into mechanical 
or electrical energy. One need draw no distinction in this regard between 
mechanical and electrical forms of energy, for each may be converted into 
the other almost without loss. But to get either from heat is another 
story. At the utmost you can convert no more than a modest fraction 
of the heat that comes from fuel: in specially favourable cases you may 
hope to convert something like a third ; the rest is scattered beyond recall. 
How to effect this conversion, through the agency of a heat-engine, is a 
matter of perpetual interest to engineers. In assessing the merits of the 
engine they have to think not only of its efficiency—that is the fraction 
_ of the heat which it succeeds in converting—but also of other characteristics 
_ which are scarcely less important: of its fitness for particular types of 
_ fuel, its convenience and ease of driving, its reliability, its endurance, its 
: bulk, its weight, its cost. The heat-engines with which we are practically 
: concerned divide themselves into two great classes. First, there are 
_ those which use steam for working substance, whether of the reciprocating 
_ or turbine type; in them the heat of the burning fuel is generated outside 
_ and has to make its way to the working substance through a containing 
_ shell. Second, there is the internal-combustion class where the heat of 
the fuel is generated within the working substance itself. To this class 
belong the gas, oil, and petrol engines that have sprung into existence 
_ within the memory of many persons now living and have profoundly 
changed our habits and our outlook. Nothing perhaps has done more 
than the internal-combustion engine to make obsolete the Victorian 
sa attitude to life. Between the two classes of heat-engines there is a rivalry ; 
one might almost say a sort of war. Each has fields of operation where its 
Sant hardly admits of doubt, but there are disputed regions in which 
e find a lively contest. As sporting critics we must recognise the merits 
of both combatants. Here, surely, is a suitable subject for an address 
_ from one who is old enough to remember patting the rivals on the head 
_ when they were boys. He now draws up his easy chair, taking care not 
_ to put it too near the ropes, and proceeds to make such comments as he 
may about the game. 
_ A quarter of a century ago I presided over Section G and now the 
“honour is unexpectedly repeated : I am taken off the shelf, dusted and set 
to function. It would seem that the Council’s policy in this happy 
centenary is to trot out some of the veterans, for the entertainment, let 
us hope, of less fallible youth. Before asking me to act as President of 
the Section, they had invited me to give the Bramwell Lecture, and I could 
accept the two duties only through their kindness in allowing one address 
_to serve for both. 
