DO Rayleigtis Address to the British Association. 



It is not necessary that I should review in detail the work of 

 Siemens. The part which he took, during recent years, in the 

 development of the dynamo machine must be known to many of 

 you. We owe to him the practical adoption of the method, first 

 suggested by Wheatstone, of throwing into a shunt the coils of 

 the field magnets, by which a greatly improved steadiness of 

 action is obtained. The same characteristics are observable 

 throughout — a definite object in view and a well directed perseve- 

 rance in overcoming the difficulties by which the path is usually 

 obstructed. 



These are, indeed, the conditions of successful invention. The 

 world knows little of such things, and regards the new machine 

 or the new method as the immediate outcome of a happy idea. 

 Probably, if the truth were known, we should see that, in nine 

 cases out of ten, success depends as much upon good judgment 

 and perseverance as upon fertility of imagination. The labors of 

 our great inventors are not unappreciated, but I doubt whether 

 we adequately realize the enormous obligations under which we 

 lie. It is no exaggeration to say that the life of such a man as 

 Siemens is spent in the public service ; the advantages which he 

 reaps for himself being as nothing in comparison with those which 

 he confers upon the community at large. 



As an example of this it will be sufficient to mention one of 

 the most valuable achievements of his active life — his introduc- 

 tion, in conjunction with his brother, of the regenerative gas 

 furnace, by which an immense economy of fuel (estimated at 

 millions of tons annually) has been effected in the manufacture of 

 steel and glass. The nature of this economy is easily explained. 

 Whatever may be the work to be done by the burning of fuel, a 

 certain temperature is necessary. For example, no amount of 

 heat in the form of boiling water, would be of any avail for the 

 fusion of steel. When the products of combustion are cooled 

 down to the point in question, the heat which they still contain 

 is useless as regards the purpose in view. The importance of this 

 consideration depends entirely upon the working-temperature. 

 If the object be the evaporation of water or the warming of a 

 house, almost all the heat may be extracted from the fuel without 

 special arrangements. But it is otherwise when the temperature 

 required is not much below that of combustion itself, for then the 



