PRESIDENTIAL ADDRESS. 17 



deal of our summer heat, to any enterprising syndicate, if 

 they could make use of it. At present, in such countries, 

 the sun's rays are actually a source of waste in some ways, 

 as our perspiring bodies and languid minds, at some periods 

 of the year, sufficiently show. It is very difficult to con- 

 ceive how this enormous dissipation of energy is to be 

 prevented, but the concentration of potential energy exist- 

 ing in recently discovered substances, may give us hope. 



The moon has hitherto been useless to all, except to poets, 

 beyond its occasional light; for its action on tides is as often 

 an impediment as a help to navigation, but could the oft 

 talked of utilization of the rise and fall of the tide, for 

 mechanical power, be made economically available, much 

 of our fuel would be saved. 



As far as I know, not much seems to have been clone in 

 in the direction of reducing skin friction in ships, though 

 Froude, Sir William White, and others, have made it the 

 subject of their investigations. There is not a word of any 

 attempt to deal with the problem in the exhaustive historical 

 address of Sir William White to the Institution of Civil 

 Engineers last year. Yet the quantity of fuel consumed, 

 in overcoming this resistance, must be enormous, in the 

 great Atlantic liners of the day. And the worst of it is 

 that, as we go on increasing size, we go on, simultaneously, 

 piling up greatly increased skin friction, due to the larger 

 surface and enhanced speed. Might not that important 

 branch of science, curiously called natural history, help us 

 in solving this problem ? Observations could be made on 

 the scales of certain fishes, whose speed, in proportion to 

 their propelling power, is far greater than that of the fastest 

 ocean steamer, in order to see how their skin friction has 

 been reduced by natural selection. Long ages of quickness 

 in seizing their prey, and in constant escape from their 

 numerous enemies, must have developed a very efficient 



B— Dec. 7, 1904. 



