given on a late Trial. 336 



and found that sugar was liable to boil over at a temperature 

 of 250°, the oil at a temperature not less than 650° or 700° ; 

 that the sugar took fire at 370° by the application of flame ; 

 and the oil took fire at a temperature higher than Fahrenheit's 

 thermometer goes, suppose nearly 700° ; and that, with a view 

 to determine whether the leaden pipe might have been melted 

 by the oil process, he put some lead into the oil and 

 heated it up to 600°, and afterwards took out the lead and 

 found it uninjured.** The other parts of Mr. Barry's evidence 

 were confirmatory of the testimony which had already been 

 given by other gentlemen. 



Observation. — The result of Mr. Barry's experiment on 

 lead is what might have been expected, though it contradicts 

 the most respectable testimony; Sir Isaac Newton and Dr. 

 Lewis having given 540° as the melting point of lead, Morveau 

 590°, and Irvine 594°. Some years ago I made a series of 

 experiments on the melting points of several of the metals, and 

 found the pure lead, which I had prepared by the reduction 

 of iitliarge, would not melt till it had acquired the temperature 

 of 612°. 



Mr. Charles Silvester spoke very decidedly as to the 

 superior safety of boiling sugar by oil instead of by a naked 

 fire ; he said " he had attended in court during the examination 

 of Mr. Wilson ; that he agreed with him in the evidence he gave, 

 and did not differ from him in any thing that he was acquainted 

 with, equally with himself; that from the experiments which 

 he had witnessed he was sure it must have taken three hours 

 to raise the oil in the large vessel from 300° to 600°, even if 

 the pump had been stopped and the fire constantly attended to ; 

 that if gas were given out from that apparatus it would be in 

 very small quantities at first ; that the oil would be decomposed 

 so gradually as to let the gas escape without compression ; 

 that it would be impossible to set fire to the oil in the vessel, 

 because there could be no oxygen present, and that if the oil 

 hud leaked into the fire, no flunic could be communicated to 

 the oil in the large iron vessel." 



