442 



NATURE 



[Sept. 6, 1888 



that those who are to come after him must be trained in science, 

 so that they may readily appreciate the full value of each 

 scientific discovery as it is made. Thus the application of 

 science by the engineer not only stimulates those who pursue 

 science, but adds him to their number. 



Holding, as I have said I do, the view that he who displaces 

 unintelligent labour is doing good to mankind, I claim for the 

 unknown engineer who, in l'ontus, established the first water- 

 wheel of which we have a record, and for the equally unknown 

 engineer who first made use of wind for a motor, the title of 

 pioneers in the raising of the dignity of labour, by compelling 

 the change from the non-intelligent to the intelligent. 



With respect to these motors — wind and water — we have 

 two proverbs which discredit them: "Fickle as the wind," 

 "Unstable as water." 



Something more trustworthy was needed — something that we 

 were sure of having under our hands at all times. As a result, 

 science was applied, and the "fire" engine, as it was first 

 called, the "steam" engine, as it was re-named, a form of 

 "heat " engine, as we now know it to be, was invented. 



Think of the early days of the steam-engine — the pre- Watt 

 days. The days of Papin, Savory, Newcomen, Smeaton ! 

 Great effects were produced, no doubt, as compared with no 

 fire engine at all ; effects so very marked as to extort from the 

 French writer, Belidor, the tribute of admiration he paid to the 

 " fire" engine erected at the Fresnes Colliery by English engin- 

 eers. A similar engine worked the pumps in York Place (now 

 the Adelphi) for the supply of water to portions of London. We 

 have in his work one of the very clearest accounts, illustrated by 

 the best engravings (absolute working drawings), of the engine 

 which had excited his admiration. These drawings show the 

 open-topped cylinder, with condensation taking place below 

 the piston, but with the valves worked automatically. 



It need hardly be said that, noteworthy as such a machine 

 was, as compared with animal power, or with wind or water 

 motors, it was of necessity a most wasteful instrument as regards 

 fuel. It is difficult to conceive in these days how, for years, it 

 could have been endured that at each stroke of the engine the 

 chamber that was to receive the steam at the next stroke was 

 carefully cooled down beforehand by a water injection. 



Watt, as we know, was the first to perceive, or, at all events, 

 to cure, this fundamental error which existed prior to his time 

 in the "fire" engine. To him we owe condensation in a 

 separate vessel, the doing away with the open-topped cylinder, 

 and the making the engine double-acting ; the parallel motion ; 

 the governor ; and the engine-indicator, by which we have 

 depicted for us the way in which the work is being performed 

 within the cylinder. To Watt, also, we owe that great source 

 of economic working — the knowledge of the expansive force of 

 steam ; and to his prescience we owe the steam-jacket, without 

 which expansion, beyond certain limits, is practically worthless. 

 I have said "prescience "—fore-knowledge — but I feel inclined 

 to say that, in this case, prescience maybe rendered " pre- 

 Science," for I think that Watt felt the utility of the steam- 

 jacket, without being able to say on what ground that utility 

 was based. 



I have already spoken in laudatory terms of Tredgold, as 

 being one of the earliest of our scientific engineering writers, 

 but, as regards the question of steam-jacketing, Watt's prescience 

 was better than Tredgold's science, for the latter condemns the 

 steam-jacket, as being a means whereby the cooling surfaces are 

 enlarged, and whereby, therefore, the condensation is increased. 



I think it is not too much to say that engineers wh">, since 

 Watt's days, have produced machines of such marvellous 

 power — and, compared with the engines of Watt's days, of so 

 great economy — have, so far a- principles are concerned, gone 

 upon those laid down by Watt. Details of the most necessary 

 character — necessary to enable those principles to be carried out — 

 have, indeed, been devised since the days of Watt. Although 

 it is still a very sad confession to have to make, that the very 

 best of our steam-engines only utilizes about one- sixth of the 

 work which resides (if the term may be used) in the fuel that is 

 consumed, it is, nevertheless, a satisfaction to know that great 

 economical progress has been made, and that the 6 or 7 pounds 

 of fuel per horse-power per hour consumed by the very best 

 engines of Watt's days, when working with the aid of condensa- 

 tion, is now brought down to about one-fourth of this consump- 

 tion ; and this in portable engines, for agricultural purposes, 

 working without condensation — engines of small size, developing 

 only 20 horse-power ; in such engines the consumption has been 

 reduced to as little as 1 "85 pound per brake horse-power per 



hour, equal to I "65 pound per indicated horse-pcwer per hour, 

 as was shown by the trials at the Royal Agricultural Society's 

 meeting at Newcastle last year — trials in which I had the 

 pleasure of participating. 



In these trials Mr. William Anderson, one of the Vice- 

 Presidents of Section G, and I were associated, and, in making 

 our report of the results, we adopted the balance-sheet system, 

 which I suggested and used so long ago as 1873 (see vol. lii., 

 pp. 154 and 155, of the Minutes of Proceedings of the Institu- 

 tion of Civil Engineers"), and to which I alluded in my address 

 as President of Section G at Montreal. 



I have told you that the engineer of the present day appreciates 

 the value of the "next-to-nothings." There is an old house- 

 keeping proverb that, if you take care of the farthings and the 

 pence, the shillings and the pounds will take ca: - e of themselves. 

 Without the balance-sheet one knows that for the combustion of 

 1 pound of coal, the turning into steam of a given quantity of 

 water at a given pressure is obtained. It is seen, at once, that 

 the result is much below that which should be had, but to 

 account for the deficiency is the difficulty. The balance-sheet, 

 dealing with the most minute sources of loss — the farthings and 

 the pence of economic working — brings you face to face with 

 these, and you find that improvement must be sought in paying 

 attention to the "next-to-nothings." 



Just one illustration. The balance-sheet will enable you at a 

 glance to answer this among many important questions : Has 

 the fuel been properly burnt — with neither too much air, nor 

 too little? 



At the Newcastle trials our knowledge as to whether we had 

 the right amount of air for perfect combustion was got by an 

 analysis of the waste gases, taken continuously throughout the 

 whole number of hours' run of each engine, affording, therefore, 

 a fair average. The analysis of any required portion of gases 

 thus obtained was made in a quarter of an hour's time by the aid 

 of the admirable apparatus invented by Mr. Stead, and, on the 

 occasion to which I refer, manipulated by him. In one instance 

 an excess of air had been supplied, causing a percentage of loss 

 of 6'34 In the instance of another engine there was a deficiency 

 of air, resulting in the production of carbonic oxide, involving a 

 loss of 4 per cent. The various percentages of loss, of which 

 each one seems somewhat unimportant, in the aggregate 

 amounted to 28 per cent., and this with one of the best boilers. 

 This is an admirable instance of the need of attention to 

 apparently small things. 



I have already said that we now know the steam-engine is 

 really a heat engine. At the York meeting of our Association I 

 ventured to predict that, unless some substantive improvement 

 were made in the steam-engine (of which improvement, as yet, 

 we have no notion), I believed its days, for small powers, were 

 numbered, and that those who attended the centenary of the 

 British Association in 1931 would see the present steam-engines 

 in museums, treated as things to be respected, and of antiquarian 

 interest to the engineers of those days, such as are the open- 

 topped steam cylinders of Newcomen and of Smeaton to our- 

 selves. I must say I see no reason, after the seven years which 

 have elapsed since the York meeting, to regret having made 

 that prophecy, or to desire t> withdraw it. 



The working of heat engines, without the intervention of the 

 vapour of water, by the combustion of the gases arising from 

 coal, or from coal and from water, is now not merely an esta- 

 blished fact, but a recognized and undoubted, commercially 

 economical, means of obtaining motive power. Such engines, 

 developing from 1 to 40 horse-power, and worked by the 

 ordinary gas supplied by the gas mains, are in most extensive 

 use in printing-works, hotels, clubs, theatres, and even in large 

 private houses, for the working of dynamos to supply electric 

 light. Such engines are also in use in factories, being some- 

 times driven by the gas obtained from "culm" and steam, and 

 I are giving forth a horse-power for, it i; stated, as small a 

 consumption as I pound of fuel per hour. 



It is hardly necessary to remind you — but let me do it — that, 

 although' the saving of half a pound of fuel per horse-power 

 appears to be insignificant, when stated in that bald way, one 

 realizes that it is of the highest importance when that half-pound 

 turns out to be 33 per cent, of the whole previous consumption 

 of one of those economical engines to which I have referred. 



The gas-engine is no new thing. As long ago as 1807 a M. 

 de Rivaz proposed its use for driving a carriage on ordinary 

 roads. For anything I know, he may not have been the first 

 proposer. It need hardly be said that in those days he had not 

 illuminating gas to resort to, and he proposed to employ hydro- 



