14 



importance of the manufacture of iron, he thought it was 

 deserving of great consideration whether the use of the hot 

 blast would effect the purposes of the cold blast at a cheaper 

 rate. The quantity of iron manufactured in England is 

 now double what it was some years ago. It had been said 

 that the hot blast would produce double the quantity pro- 

 duced by the cold blast, but then they must consider whether 

 the quality of the former, was equal to that of the latter. 

 Mr. Hartop had said it was not. He did not consider that 

 the tests used in these experiments were to be depended upon. 

 For the force exercised by a man's arm was very variable ; and 

 it might be to the interest of the striker to make it so. If 

 he were interested in the hot blast, the blow might be very 

 weak, and if he were interested in the cold blast, it might be 

 much heavier. He would suggest for the proper testing of 

 this matter, that the bars of iron intended for experiment 

 should be placed upon equal bearings, and that the weights 

 should fall from the same elevation. If, therefore, the ques- 

 tion of hot and cold blasts were to be discussed, the data 

 must be more complete than those now before then. For- 

 merly iron could only be made with charcoal, and it was 

 then said that coke would not make iron of so good a 

 quality ; but coke is now used in great abundance, and has 

 given employment to vast numbers of people. Hot and cold 

 blasts might therefore be considered in the same relative 

 position to each other, as were formerly charcoal and coke. 



A Paper was then read 



ON THE MOLECULAR CHANGE IN THE CONSTITUTION OF 

 WROUGHT IRON FROM THE EFFECTS OF VIBRATION 



AND CONCUSSION BY RICHARD SOLLY, ESQ., OF 



SHEFFIELD. 



Mr. Solly exhibited a portion of an iron pin, which af- 

 forded an instance of the crystallization of fibrous malleable 

 iron by the effects of vibration. The iron, of which this pin 



