■49 



Section G.— MECHANICAL SCIENCE. 

 President of the Section — T. Forster Brown, Esq., M.Inst. C.E. 



THURSDAY, AUGUST 20. 

 The President delivered the following Address : — 



I FEEL extremely diffident in assuming the Presidential Chair of Section G at the 

 present meeting of the British Association. 



The addresses of my eminent predecessors have, year by year, in the best 

 language, and in the most condensed form, gauged the progress of, and indicated 

 the direction in which, further improvements in mechanical science may be looked 

 for. In so large a field as that of mechanical engineering my somewhat limited 

 knowledge will not admit of my following very closely in their footsteps ; but 

 possibly, by tracing tlie modern practice of this branch as applied to mining opera- 

 tions in Great Britain, I may be able to submit some points of interest to mechanical 

 engineers. 



Great progress has been made in mechanical science since the British Associa- 

 tion met in the Principality of Wales eleven years ago ; and some of the results 

 of that progress are exemplified in our locomotives, marine engineering, and in such 

 works as the Severn Tunnel, the Forth and Tay Bridges, and the Manchester Ship 

 Canal, which is now in progress of construction. 



In mining, the progress has been slow, and it is a remarkable fact that, with 

 the exception of pumping, the machinery in use in connection with mining opera- 

 tions in Great Britain has not, in regard to economy, advanced so rapidly as has 

 been the case in our manufactures and marine. 



This is probably due, in metalliferous mining, to the uncertain nature of the 

 mineral deposits not aSbrding any adequate security to adventurers that the 

 increased cost of adopting improved appliances will be reimbursed ; whilst in coal 

 mining, the cheapness of fuel, the large proportion which manual labour bears to 

 the total cost of producing coal, and the necessity for producing large outputs with 

 the simplest appliances, explain, in some measure, the reluctance with which high- 

 pressure-steam compound engines, and other modes embracing the most modern 

 and approved types of economising power, have been adopted. 



Metalliferous mining, with the exception of the working of iron ore, is not in 

 a prosperous condition owing to causes to which it is unnecessary to refer ; but in 

 special localities, where the deposits of minerals are rich and profitable, progress has 

 been made within a recent period by the adoption of more economical and efficient 

 machinery. 



For example, at the Tincroft Tin Mine, in Cornwall, a compound winding plant 

 has been erected by Messrs. Harvey, of Hayle, of which the following are par- 

 ticulars : The high-pressure cylinder is 17 inches in diameter and steam-jacketed, 

 and the low-pressure cylinder is 30 inches in diameter, each having a stroke of 

 6 feet. A condenser is worked by levers off" the crosshead of the low-pressure 

 cylinder. The drum is 8 feet 6 inches in diameter, and of the plain cylindrical type. 

 The engine is fitted with steam reversing gear, and an auxiliary steam valve for 



