TRANSACTIONS OF SECTION G. 791 



constituent of nature, each molecule of matter Laving its own definite charge, 

 which determines its attraction and its repulsion. All attempts to revive the 

 rrankliuian, or material theory of electricit}', have, however, to be so loaded with 

 assumptions, and so weighted with contradictions, that they completely fail to 

 remove electricity from the region of the mysterious. It is already extremelj^ 

 difficult to conceive the existence of the ether itself as an infinitely thin, highly 

 elastic medium, filling all space and employed only as the vehicle of those undulatory 

 motions that give us light and radiant heat. The material theory of electricity 

 requires us to add to this another incomprehensible medium embedded or entangled 

 in this ether, which is not only a medium for motion, but which is itself moved. 

 The practical man, with his eye and his mind trained by the stern realities of daily 

 experience, on a scale vast compared with that of the little world of the laboratory, 

 revolts from such wild hypotheses, such unnecessary and inconceivable concep- 

 tions, such a travesty of the beautiful simplicity of nature. 



He has a clear conception of electricity as something which has a distinct objec- 

 tive existence, which he can manufacture and sell, and something which the un- 

 philosophic and ordinary member of society can buy and use. The physicist 

 asserts dogmatically : ' Electricity may possilDly be a form of matter — it is not a 

 form of energy.' The engineer says distinctly : 'Electricity is a form of energy — it 

 is not a form of matter ; it obeys the two great developments of the present 

 generation — the mechanical theory of heat and the doctrine of the conservation of 

 energy.' There must be some cause for this strange diflference of views. It is 

 clear that the physicist and the engineer do not apply the term electricity to the 

 same thing. The engineer's electricity is a real form of energy ; the speculative 

 philosopher's electricity is a vague subjective imreality which is only a mere 

 factor of energy and is not energy itself. This factor, like force, gravity, life, must, at 

 any rate for the present, remain unknowable. It is not known what force is ; neither 

 do we know what is matter or gravity. The metaphysician is even doubtful as 

 regards time and space. Our knowledge of these things commences with a defini- 

 tion. The human mind is so unimpressionable, or language is so poor, that writers 

 often cannot agree even on a definition. The definition of energy is capacity for 

 doing work. We practical men are quite content to start from this fiducial line, 

 and to aftirm that our electricity is a something which has a capacity for doing 

 work ; it is a peculiar form of energy. The physicist may speculate as much as 

 he pleases on the other side of this line. He may take the factors of energy, and 

 mentally play with them to his heart's content ; but he must not rob the engineer 

 of his term electricity. It is a pity that we cannot settle our difference by chang- 

 ing the term. Physicists might leave the term electricity to the form of energy, 

 which is an objective reality, and which the ordinary mortal understands ; while 

 engineers would be quite content if speculative physicists and enthusiastic mathe- 

 maticians would call their subjective unreality, their imaginary electrical matter, 

 by some other term. If it be necessary to mentally create some imaginary matter to 

 fulfil the assumptions and abstractions of their mathematical realisations, let them 

 call it coulombism or electron, and not appropriate the engineer's generic and com- 

 prehensive term electricity. The engineer finds the motions of existing matter 

 and of the ether quite sufficient to meet all his requirements, and to account for all 

 those phenomena which are called electrical. 



It seems paradoxical to assert that two unrealities can form a reality, or that 

 two subjective ideas can become an objective one ; but it must be remembered that 

 in all electrical phenomena that which makes them real and objective is derived 

 from without. The motion that renders an electrical phenomenon evident is im- 

 parted to it from some other form of energy. The doctrine of the conservation of 

 energy asserts that energy is never destroyed, it is only transformed — work must 

 be done to render it evident. No single electrical effect can be adduced which is 

 not the result of work done, and is not the equivalent of energy absorbed. The 

 engineer's notions of work — something done against resistance — and of power — the 

 rate at which this change of condition is effected — are the keystones to the con- 

 ception of the character of those great sources of power in nature whose direction 

 to the uses and convenience of man is the immediate profession of those who 



