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Mr. Spence was the first practical cliemist to draw atten- 

 tion to the fallacy that to completely burn coal-smoke was 

 to purify the atmosphere of our manufacturing towns. He 

 made a series of examinations of the air in and around Man- 

 chester, and demonstrated that it contained practically as 

 much sulphurous acid on Sundays when the smoky factory 

 chimneys were stopped, and the house chimneys only were 

 going, as on ordinary days of the week. 



About 14 years ago, on the occurrence of a railway accident 

 which appeared to confirm the general belief that intense 

 cold causes iron to fracture, Mr. Spence made a series of 

 comparative trials of the strength of iron at ordinary tem- 

 peratures and of the same when reduced to zero Fahr., and 

 in a paper read before the Manchester Literary and Philo- 

 sophical Society, he declared the result to be that cold in- 

 creases instead of decreases the strength of iron. Dr. Joule 

 showed at the same time that experiments which he had 

 undertaken led him practically to the same conclusion. 



At the Exeter meeting of the British Association in 1869, 

 Mr. Spence having stated before the Chemical Section that 

 steam at 212° Fahr. could be made to raise the temp, of 

 saline solutions to their boiling point however high that 

 point might be, and that acetate of potash, for example, 

 could be readily raised by its means to a temp, of 886° Fahr. 

 his statement was received with incredulity ; but on his 

 demonstrating its correctness by actual experiment the 

 result appeared so anomalous that Professor Williamson 

 declined to accept it until he had himself examined the 

 thermometer. This being found in order, a little reflection 

 soon made it obvious to the Professor that the latent heat 

 evolved by the condensing steam had become sensible heat 

 measurable by the thermometer ! The phenomenon had been 

 familiar to Mr. Spence for many years in connection with his 

 process for dissolving alum on the large scale. The discovery^ 

 as has been pointed out by Mr. Stanford, President of the 



