TllAXtJACTIONS OF SKCTION G. 



877 



linti'llt'ctiial activity excited by the work wliich the civil engineers of J']iiphind had 

 ' iiccoiuplishod tliat pave to pliilo.«o])hy the theory of tlic conservation of energy 

 ' iiifluding the dynamical theory of heat. . . . Tht! enginet;i-ing genius of tlie future 

 ' is certain to derive from tliis theory strength and guidance. Thus necessarily has 

 'thought originated fact, and fact originated thought. In the development of 

 ' science these two powers are coef[Ual ; each in turn ceasing to he a consequence, 

 ■and becoming a creative; cause. 'I'he Atlantic cable also had its small beginnings 

 ■intlie laboratory of tlie jihysicnl inquirer. Here, as before, experimental physics 

 •led the way to engineering facts of astounding magnituile and skill. But here also 

 ■the positions of debtor and creditor have been reverst;d, for the work of the 

 ■eiifrineer has caused tiie pliysical inquirer to ])ur8ue his investigations with a 

 • thoroughness and vigour, and has given to tliose investigations a scope and niagni- 

 ' tilde wliich, without the practical stinndiis, would have been inipossiljle. The 

 'consequence is that the practical realisation of sending electric messages along the 

 'bottom of the Atlantic has been an immense augmentation of our liuowledge 

 'regarding electricity itself. Tluis does tlie human intelligence oscillate between 

 ■sound theory and sound practice, gaining by every contact with each an accession 

 •of strength. These two things are the s'nl and body of science. Sever sound 

 'theory from sound practice, and lioth die of atrophy. The one becomes a ghost 

 ■and the other becomes a corpse.' 



I think all men, even althougli they be f<dlowers of science in its purest and 

 most abstract form, must agree that these words are words of sound sense, well 

 wortliy of being borne in mind and of being acted on, and will, therefore, concur 

 in the propriety of Section G dealing with engineering subjects generally as well 

 as with abstract mechanical science. Once admitting this, I may :isk — 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 members of this 

 Section. Surely every one must agree that we engineers are those who make the 

 jrreatest practical use not only of the science of Mechanics but of the researches 

 and discoveries of the members of tiie other sections of tliis .\ssocintion. 



Section A, Mathematical and rhysival Scicnci'. The connection between this 

 Section and Section G is most intimate. Witli any ordinary man I should have 

 referred, in proof of this intimate connection, to tin; fact that the President of A 

 this year is a memljer of the Council of the Institution of Civil I'jigineers, but when 

 I remind you that it is Sir "William Thomson •who iills this doublt; olHce. you will 

 See that no deduction such as I have hinted at can be drawn from his dual functions, 

 teause the remarkable extent and versatility of \liis attaiiunents qualify him for so 

 many offices, that the mere fact of his holding some one double jjosition is no certain 

 evidence of the intimate connection between the two. lint 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 acimstics ; while, in 

 other branches, meteorological science, ])hotometriral science, and tidal laws are all 

 important. Without a knowledge of thermal laws, the engineer engaged in the 

 construction of heat motors, whether they bo the steam engine, the g'as engine or 

 the hot-air engine, or engines depending upon the expansion and contraction imder 

 changes of temperature of lluids or of solids, will tind himself groping in the dark; 

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

 W unable to deduce laws from them ; and if he make any progress at all, it will 

 !ii3t guide him with certainty to furtlier developnn'ut, and it may be that he will 

 ^aste time and money in tiie endeavour to obtain results which a knowledge of 

 thermal science would have shown him were impossible. Furnished, however, 

 Wh this knowledge, the engineer starting with the mechanical equivalent of heat, 

 bowing the utmost tliat is to be attained, and starting with the knowledge of 

 the calorific ellect 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 



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