PETER SPENCE 281 



One trait of his character used to exhibit 

 itself at these meetings, his aversion to take 

 anything for granted; he would try to test 

 theories and to prove facts. 



The question of the effect of cold on iron 

 was raised at one of the meetings of the 

 society. A railway accident had just occurred, 

 occasioned by the breaking of the tyres of 

 the carriage wheels. It was generally ad- 

 vanced that cold and frost made iron and 

 steel more brittle, but Dr. Joule stated that, 

 however general the impression might be, he 

 knew of no experiments that tended to prove 

 that contention to be a correct one. 



Peter Spence at once determined to make a 

 series of thorough and conclusive experiments, 

 the results of which were that he proved 

 "that a specimen of cast iron having at 70 

 Fahr. a given power of resistance to trans- 

 verse strain, will, on its temperature being 

 reduced to zero, have that power increased 

 by 3 per cent." Dr. Joule simultaneously 

 made an experiment with refrigerated needles 

 and obtained substantially the same result. 



One of the discoveries of great scientific 

 interest and practical utility made by Mr. 

 Spence was communicated by him to the 

 Chemical section of the British Association, 



