i6o 



NA TURE 



[December 18, 1902 



attractions for me for several reasons. In the first place, this 

 kind of prophecy is easy and pleasant. I might draw a rosy 

 picture of a future when everything conceivable is done elec- 

 trically. We shall have electrical energy developed direct from 

 carbon at the coal-pits. Not only all our lighting, but all our 

 domestic heating will be done electrically. There will be no 

 smoke in our cities or in what will correspond to them. Most 

 of the dirt of our houses will have vanished. Large and 

 crowded towns will have disappeared, because the telegraph 

 will have given way to its wireless rival, and that will have 

 given way to the wireless telephone with no exchanges and no 

 subscriptions. There will thus be no need for people to go and 

 see one another to transact business. Even when matters must 

 be written to preserve a record, no office will be necessary. \ou 

 will dictate by wireless telephony to your shorthand clerk at his 

 distant house. Perhaps we shall all learn shorthand instead of 

 our present cumbersome system of writing, and all books and 

 letters will be in one language, written and printed phonetically 

 at speaking speed or faster. The horse will have gone, leaving 

 clean and odourless streets, with smooth surfaces on which 

 people will travel in rapid electric automobiles. The railways 

 with very rapid long-distance service will be entirely electric. It 

 is very easy to prophesy in this sort of way, not only in a general 

 way, but in considerable detail ; and it is an amusement that 

 brings much credit to the prophet. If any of his prophecies 

 seem unlikely to come true, he merely has to say, " Wait a 

 little !" While if anything like what he foretells comes into 

 existence, say twenty years hence, all he has to do is to refer 

 back to an address to claim that he has foretold it, and the 

 future inventor will have half his credit taken from him and 

 given to the prophet. If the prophecies are sufficiently vague, 

 there is certain to be some sort of fulfilment of some of them 

 sooner or later, and it is always well to have a good many past 

 publications of this sort in stock waiting for future develop- 

 ment. 



Great though the temptation is, I will resist it, and try to 

 look into the future from quite a different point of view. We 

 have been going ahead so very fast lately — even our acceler- 

 ation itself increasing — that we may be a little apt to have 

 vague views of what we can and what we cannot do elec- 

 trically. It may be well, therefore, to try to look over some 

 of the branches of our great and diverse industry, and see 

 what obstacles are now opposing us and what are likely to 

 oppose us shortly, and whether the obstacles are insuperable 

 or not. This sort of prophecy is much more difficult than the 

 other, for there can be no credit twenty years hence in having 

 said something could not be done, even if it has not, while if 

 it has been accomplished the position is still more difficult. 

 Negative prophecy is thus unattractive. But the discussion of 

 our limits may not only have a beneficial effect in making us 

 modest, but it may be a much greater benefit if, by focussing 

 our attention on a limit of any development, we find either that 

 the obstacle is theoretically insurmountable, in which case we 

 must go round it, or that it has to be scaled in a particular way. 

 There are clearly at least two kinds of obstacles. For in- 

 stance, it is obviously impossible to get more than 746 watts 

 out of a dynamo taking one horse-power to drive it. But the 

 limit of possible speed on an electric railway belongs to quite a 

 different category. I will therefore discuss various branches 

 of electrical technology, to see what n.ay prevent or is preventing 

 further advance. 



Twenty years ago, this Institution was chiefly concerned with 

 the development of the telegraph. We can get but few telegraph 

 papers now. This is not because telegraphy is dead ; it is 

 because most of its problems are solved, so there is little to 

 discuss. The fact that there is little to discuss in telegraphy is 

 the proof of its vitality. It has passed out of the childhood of 

 technical difficulties into the manhood of commercial develop- 

 ment. Ten years ago, we were in the thick of the evolution of 

 the dynamo and the transformer. Now there is little but detail 

 to discuss about electrical generating machinery. This is because 

 heavy electrical machinery has got through its difficult infancy 

 and is now a trade, which is the highest compliment that can 

 be paid to it. But we electrical engineers have also developed 

 through our difficult training into being the scientific branch of 

 the engineering profession. Our exactness of calculation and 

 measurement has leavened the steam engineers and the other 

 manufacturers with whom we have to work in concert. 



No one man can be a complete electrical engineer ; but each 

 of us ought to know one subject well and a large number of 



allied subjects fairly well. As a basis of technical knowledge, 

 which I am alone dealing with to-night, we must have a fairly 

 all-round knowledge of "theoretical" physics and chemistry. 

 Physics is merely unapplied engineering. Science is split — un- 

 fortunately, the split is very difficult to heal — into two parts, 

 generally wrongly called the theory and the practice ; or pure 

 and applied science. This fissure is not so deep in our branch 

 of engineering, but it is there. Science, to be worthy of the 

 name, is knowledge of Nature utilised by man. Engineering is 

 science, and science is engineering. You can cut off a part and 

 call it unapplied science. This is what is generally known as 

 theory or pure science. It is not purer than any other science, 

 and the 'term theory is misapplied. To be an engineer you 

 must know both branches. There is nothing superior about 

 knowledge which is not yet applied. It is mere raw material ; . 

 it may be useful when worked up, and it is valuable before it is 

 worked up. but only because it may be worked up. The so-called 

 practical man who works at applications without understanding 

 the generalised principles is ignorant. He only understands a 

 part of science. The so-called scientific man who only under- 

 stands what is called pure science is just as ignorant. Each 

 understands part of his subject only. 



We as electrical engineers ought especially to heal the split 

 between the halves of science ; a split which is much deeper 

 in other branches of engineering, such as chemical and purely 

 mechanical. We ought to unite knowledge of both branches of 

 science in one individual as much as possible. 



Tides. 



The tides are often referred to as a possible source of energy 

 even to this day ; and it is urged that in places where the tide 

 rises abnormally, for instance in the estuary of the Severn, it 

 would pay to make a dam with turbines. The sort of argument 

 is that if you have an area of, say, 1000 square metres and a 

 total rise of 15 metres, you have 15,000 cubic metres of water, 

 and as this runs in twice and out twice a day, you have 15,000 

 cubic metres of water, falling the equivalent of 60 metres a 

 day, or approximately 100 kilowatts. This statement contains 

 many fallacies. In the first place, in order to get the full 

 advantage of the difference of level, the water must be let in 

 and out at high and low tide only. Even then the equivalent 

 or average head during discharge or charge is only yh metres. 

 But a system which gave an enormous power for a very short 

 time four times a day would be of no use. The plant would 

 be expensive and the result of no value. With a single tank it 

 is impossible to get a continuous output. If the tide is coming 

 in and you get power by letting the tide fill the tank, the 

 power will decrease to zero as the tide begins to fall and comes 

 to the same level as the water in the tank. It is therefore neces- 

 sary to have more than one tank. To make the plant practical, 

 you want fairly constant pressure available on the turbines, 

 though you may waste head by sluices or valves. It is often 

 said that a Norwegian fiord or a Scotch loch could be easily 

 dammed and utilised, but it would be impossible to find three 

 lochs all opening out together. The need for more than one 

 reservoir does not seem to have been recognised. In addition, 

 the demand for electrical energy on Scotch lochs or Norwegian 

 fiords is rather minute. 



Water Power. 



Some years ago, there was a great deal of excitement about 

 the development of water powers. The possibility of " harness- 

 ing Niagara" and utilising waterfalls all over the world was 

 hailed as a great triumph over Nature, and the idea was that 

 power could begot for nothing, and industries would all migrate 

 from coal districts to the neighbcurhood of water powers. The 

 daily Press and the magazines took the matter up, and there is 

 something in the idea of saving some of the colossal waste of 

 natural energy that appealed especially to the half-scientific or 

 unpractical reader. At the time of the excitement, it was pointed 

 out, largely in vain, that water power did not cost nothing, 

 because the development of a fall demanded a good deal of 

 capital, on which interest and depreciation had to be paid. But 

 further than this, Ricardo's theory of rent is applicable to water 

 powers as well as to arable land. If steam power costs a 

 farthing a unit, and if water power at the same place can be pro- 

 duced lor half a farthing, after paying working expenses and inter- 

 est, the owner of the water power will claim the odd half farthing 

 as rent, or will just allow the water power enough to encourage 

 the production of a new thing. As a rule, however, a water 



NO. I/29, VOL. 6/] 



