394 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



EFFECT OF COLD ON IRON AND STEEL. 



For many years it has been almost an axiom among -civil 

 engineers that great cold tended to produce a brittle condi- 

 tion of iron and steel, and that by this hypothesis might be 

 explained the alleged increase in the percentage of railway 

 accidents by the breaking of tires and axles during the cold 

 season as compared with the warm. A communication be- 

 fore the Literary and Philosophical Society of Manchester, by 

 Mr. Brockbank, maintained the view just stated ; but in the 

 discussion which followed several eminent engineers entered 

 their protest against it, and adduced facts which tend to an 

 entirely opposite conclusion. According to Dr. Joule, numer- 

 ous experiments by himself and others proved that, so far 

 from iron and steel being weakened by cold, they are actual- 

 ly made positively stronger, resisting shocks and strains be- 

 fore which they yielded when brought to a higher tempera- 

 ture. While not denying the fact of the greater frequency 

 of fractures during the cold weather, Dr. Joule refers these to 

 the increased hardness of the ground by freezing, by which 

 the iron is subjected to a greater strain or shock than under 

 ordinary circumstances. 12 A, January 26, 253. 



INFLUENCE OF COLD ON THE STRENGTH OF IRON. 



We have referred to the experiments of Mr. Brockbank 

 in regard to the influence of cold upon the elasticity and 

 strength of iron, and to the theory of M. Joule and others 

 that cold, instead of weakening iron, actually adds to its 

 strength. Mr. Peter Spence has lately presented to the Phil- 

 osophical Society of Manchester a further communication on 

 this subject, in which he expresses his adhesion to the opin- 

 ions of M. Joule, and has no hesitation in stating it as a law, 

 that a specimen of cast-iron having at 70 Fahrenheit a given 

 power of resistance to transverse strain, will, when reduced 

 to the temperature of zero, have that power increased by 

 three per cent. After the reading of this paper, Mr. James 

 Garrick queried whether the results were legitimately dedu- 

 cible from the experiments mentioned by Mr. Spence, and 

 thought that, for reasons adduced, the iron must have been 

 of an inferior quality, and unfit for the purpose of reliable 

 experiments. The impression, however, at the present time 



