Sept. n, 1884] 



NA TURE 



473 



plished that gave to philosophy the theory of the conservation of 

 energy, including the dynamical theory of heat. . . . The engi- 

 neering genius of the future is certain to derive from this theory 

 strength and guidance. Thus necessarily has thought originated 

 fact, and fact originated thought. In the development of 

 science these two powers are coequal ; each in turn ceasing to 

 be a consequence, and becoming a creative cause. The Atlantic 

 cable also had its small beginnings in the laboratory of the 

 physical inquirer. Here, as before, experimental physics led 

 the way to engineering facts of astounding magnitude and skill. 

 But here also the positions of debtor and creditor have been 

 reversed, for the work of the engineer has caused the physical 

 inquirer to pursue his investigations with a thoroughness and 

 vigour, and has given to those investigations a scope and mag- 

 nitude, which, without the practical stimulus, would have been 

 impossible. The consequence is that the practical realisation 

 of sending electric messages along the bottom of the Atlantic 

 has been an immense augmentation of our knowledge regard- 

 ing electricity itself. Thus does the human intelligence oscil- 

 late between sound theory and sound practice, gaining by 

 every contact with each an accession of strength. These two 

 things are the soul and body of science. Sever sound theory 

 from sound practice, and both die of atrophy. The one becomes 

 a ghost and the other becomes a corpse." 



I think all men, even although they be followers of science in 

 its purest and most abstract form, must agree that these words 

 are words of sound sense, well worthy of being borne in mind 

 and of being acted on, and will, therefore, concur in the pro- 

 priety of Section G dealing with engineering subjects generally 

 as well as with abstract mechanical science. Once admitting 

 this, I may ask — certain what the answer must be — whether 

 there is any body of men who more appreciate and make 

 greater use of the applications of pure science than do the mem- 

 bers of this Section. Surely every one must agree that we 

 engineers are those who make the greatest practical use not 

 only of the science of mechanics but of the researches and 

 discoveries of the members of the other Sections of this 

 Association. 



Section A, Mathematical and Physical Science. The con- 

 nection between this Section and Section G is most inti- 

 mate. With any ordinary man I should have referred, in 

 proof of this intimate connection, to the fact that the Presi- 

 dent of A this year is a member of the Council of the Insti- 

 tution of Civil Engineers, but when I remind you that it is 

 Sir William Thomson who fills this double office, you will see 

 that no deduction such as I have hinted at can be drawn from 

 his dual functions, because the remarkable extent and ver- 

 satility of his attainments qualify him for so many offices, that 

 the mere fact of his holding some one double position is no 

 certain evidence of the intimate connection between the two. 

 But setting aside this fact of the occupancy of the chair of A by 

 a civil engineer, let us remember that the accomplished engineer 

 of the present day must be one well grounded in thermal science, 

 in electrical science, and for some branches of the profession in 

 the sciences relating to the production of light, in optical science, 

 and in acoustics ; while, in other branches, meteorological science, 

 photometrical science, and tidal laws are all-important. With- 

 out a knowledge of thermal laws, the engineer engaged in the 

 construction of heat-motors, whether they be the steam-engine, 

 the gas-engine, or the hot-air engine, or engines depending upon 

 the expansion and contraction under changes of temperature of 

 fluids or of solids, will find himself groping in the dark ; he 

 will not even understand the value of his own experiments, and 

 therefore will be unable to deduce laws from them ; and if he makes 

 any progress at all, it will not guide him with certainty to further 

 development, and it may be that he will waste time and money 

 in the endeavour to obtain results which a knowledge of thermal 

 science would have shown him were impossible. Furnished, 

 however, with this knowledge, the engineer, starting with the 

 mechanical equivalent of heat, knowing the utmost that is to be 

 attained, and starting with the knowledge of the calorific effect 

 of different fuels, is enabled to compare the results that he 

 obtains with the maximum, and to ascertain how far the one 

 falls short of the other ; he sees even at the present day that 

 the difference is deplorably large, but he further sees in the case 

 of the steam-engine, that which the pure scientist would not so 

 readily appreciate, and that is, how a great part of this loss is 

 due to the inability of materials to resist temperature and pres- 

 sure beyond certain comparatively low limits ; and he thus per- 

 ceives that unless some hitherto wholly unsuspected, and appar- 

 ently impossible, improvement in these respects should be made, 



practically speaking the maximum of useful effect must be far 

 below that which pure science would say was possible. Never- 

 theless, he knows that within the practical limits great improve- 

 ments can be made ; he can draw up a debtor and creditor account, 

 as Dr. Russell and myself have done, and as has been done by 

 Mr. William Anderson, the engineer, in the admirable lecture 

 he gave at the Institution of Civil Engineers in December last, 

 on " The Generation of Steam and the Thermodynamic Prin- 

 ciples involved." Furnished with such an account the engineer 

 is able to say, in the language of commerce, I am debtor to the 

 fuel for so many heat-units, how, on the credit side of my account, 

 do I discharge that debt ? Usefully I have done so much work, 

 converted that much heat into energy. Uselessly I have raised 

 the air needed for combustion from the temperature of the atmo- 

 sphere to that of the gases escaping by the chimney ; and he 

 sets himself to consider whether some portion of the heat cannot 

 be abstracted from these gases and be transmitted to the in-com- 

 ing air. As was first pointed out by Mr. Anderson, he will 

 have to say a portion of the heat has been converted into energy 

 in displacing the atmosphere, and that, so far as the gaseous 

 products of the coal are concerned, must, I fear, be put up with. 

 He will say, I have allowed more air than was needed for com- 

 bustion to pass through the fuel, and I did it to prevent another 

 source of loss — the waste which occurs when the combustion is 

 imperfect ; and he will begin to direct his attention to the use 

 of gaseous or of liquid fuel, or of solid fuel reduced to fine dust, 

 as by Crampton's process, as in these conditions the supply may 

 be made continuous and uniform, and the introduction of air 

 may be easily regulated with the greatest nicety. He will say, 

 I am obliged to put among my credits — loss of heat by convec- 

 tion and radiation, loss by carrying particles of water over with 

 the steam, loss by condensation within the cylinder, loss by 

 strangulation in valves and passages, loss by excessive friction or 

 by leakage ; and he will as steadily apply himself to the extinc- 

 tion or the diminution of all such causes of loss as a prudent 

 Chancellor of the Exchequer would watch and cut down every 

 unproductive and unnecessary expenditure. It is due to the 

 guidance of such considerations as these that the scientific engi- 

 neer has been enabled to bring down the consumption of fuel in 

 the steam-engine, even in marine engines such as those which 

 propelled the ship that brought us here, to less than one-half of 

 that which it was but a few years back. It is true that the daily 

 consumption may not have been reduced, that it may be even 

 greater, but if so it arises from this, that the travelling public 

 will have high speed, and at present the engineer, in his capacity 

 of naval architect, has not seen how — notwithstanding the great 

 improvements that have been made in the forms of vessels — to ob- 

 tain high speed without a large expenditure of power. I anticipate, 

 from the application of thermal science to practical engineering, 

 that great results are before us in those heat-motors, such as the 

 gas-engine, where the heat is developed in the engine itself. 

 Passing away from heat-motors, and considering heat as applied 

 to metallurgy, from the time of the hot blast to the regenera- 

 tive furnace, it is due to the application of science by the engi- 

 neer that the economy of the hqt blast was originated, and that 

 it has been developed by the labours of Lowthian Bell, Cowper, 

 and Cochrane. Equally due to this application are the results 

 obtained in the regenerative furnace, in the dust furnace of 

 Crampton, and in the employment of liquid fuel, and also in 

 operations connected with the rarer metals, the oxygen furnace, 

 and the atmospheric gas furnace, and, in its incipient stage, the 

 electrical furnace. To a right knowledge of the laws of heat 

 and to their application by the engineer, must be attributed the 

 success that has attended the air-refrigerating machines, by the 

 aid of which fresh meat is, at the end of a long voyage, delivered 

 in a perfect condition ; and to this application we owe the 

 economic distillation of sea-water by repeated ebullitions and 

 condensations at successively decreasing temperatures, thus con- 

 verting the brine that caused the Ancient Mariner to exclaim, 

 "Water, water everywhere, nor any drop to drink," into the 

 purest of potable waters, and thereby rendering the sailor inde- 

 pendent of fresh-water storage. 



With respect to the application by the engineer of electrical 

 science, it is within the present generation that electricity has 

 passed from the state of a somewhat neglected scientific abstrac- 

 tion into practical use : first, by the establishment of the land 

 telegraph, then by the development into the submarine cable, 

 by means of which any one of us visitors here in Canada may be 

 in instant communication with his own country, and may be so 

 without a selfish exclusive occupation of the cable, for once more 

 the application of science has solved that apparently impossible 



