Work Done by British Association Committees, 59 



During the period from 1830 to i860 a vast increase 

 in the use of steam power for manufacturing purposes took 

 place, and steamships came into existence capable of making 

 long sea voyages. Among the matters of importance on 

 which information was deficient at the time, not the 

 least was the provision of adequate strength in boilers, 

 since the problems arising from increase of steam pressure have 

 always been prominent, and steam pressure has steadily risen 

 since the days of Watt. Accordingly there were found in the 

 records of the Association the investigations of Fairbairn on 

 the effects of temperature on the strength of wrought iron in 

 1856, and on the collapse of circular flues in 1857. This latter 

 may be described as formmg the foundation for the design of 

 all furnace flues since, and is still the ruling authority in this 

 matter, its conclusions having been early embodied in the rules 

 for the strength of circular marine boiler furnaces adopted by 

 ihe Board of Trade, as well as in the principles of design used 

 by all the leading manufacturers of land boilers of the Cornish 

 and Lancashire types. About i860 another matter connected 

 with the strength of iron and steel came into greater promi- 

 nence than before, namely, the effects on the material of 

 repeated loadings and unloadings, reversal of stress from 

 tension to compression and vice versa at short intervals, 

 and of vibration. Again here we find the most impor- 

 tant part of the early woik reported on by the British 

 Association, beginning about i860. This work was, some seven 

 or eight years later, taken up by the Prussian Government in 

 a more thoiough and complete manner than could have been 

 effected with the resources ol: the Association, and has been 

 continued at Government expense ever since. It is of a kind 

 which must unavoidably take up much time to carry out. 



Another matter which occupied much attention for a good 

 many years was the performance of steamships in respect of the 

 relations of power and speed. Up to about 1865 little real 

 progress was made owing largely to false impressions as to the 

 importance of details of form, and the consequent controversies 



