ADDItESS. 



These art, indeed, the conditions of snccessful 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 wore known, wo should see that, in nine cases out of ten, success 

 depends as much upon good judgment and perseverance as upon fertility 

 of imagination. The labours of our great inventors are not unappreciated, 

 but I doubt whether we adequately realise the enormous obligations 

 under which we lie. It is no exaggeration to say that the life of such i 

 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 bo sufficient to mention one of the 

 most valuable achievements of his active life — his introduction, in con- 

 junction with his brother, of the Regenerative Gas Furnace, by which 

 an immense economy of luel (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 temf)erature is necessary. 

 For example, no amount of heat in the form of boiling water would 

 bo of any avail for the fusion of steel. When the products of com- 

 bustion ai'e cooled down to the point in question, the hccat 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 escaping gases carry 

 away with them the larger part of the whole heat developed. It was to 

 meet this difficulty that the regenerative furnace was devised. The pro- 

 <iucts of combustion, before dismissal into the chimney, are caused to 

 pass through piles of loosely stacked fire-brick, to which they give up 

 their heat. After a time the fire-brick, upon which the gases first 

 impinge, becomes nearly as hot as the furnace itself. By suitable valves 

 the burnt gases are then diverted thi'ough another stack of brickwork, 

 which they heat up in like manner, while the heat stored up in the first 

 etack is utilised to warm the unburnt gas and air on their way to the 

 furnace. In this way almost all the heat developed at a high temperature 

 ■during the combustion is made available for the work in hand. 



As it is now several years since your presidential chair has been occu- 

 pied by a professed physicist, it may naturally be expected that I should 

 attempt some record of recent progress in that branch of science, if indeed 

 such a term be applicable. For it is one of the difficulties of the task that 

 subjects as distinct as Mechanics, Electricity, Heat, Optics and Acoustics, 

 to say nothing of Astronomy and Meteorology, are included under Physics. 



