336 On the Chemical Evidence 



The next person called was Mr. J. T. Cooper, lecturer on 

 chemistry at the Russel Institution. He stated that if gas 

 should be produced in an apparatus that corresponds with the 

 model in court, " it would all go off up the steam-vent, even if 

 it were generated at the rate of 500 cubic feet a minute ; that 

 in heating oil, when he had got it to a certain temperature, he 

 found it difficult to add to it ; that in one experiment it took 

 forty minutes to raise it from 200° to 350° ; whereas, to bring 

 it from 350° up to 600° or 610°, it required nearly two hours 

 and a half more ; and, at last, he could hardly elevate it at all, 

 though the fire was regularly supplied the whole time. 



Robert Hendrie, Esq., being next examined, related that 

 " he had applied his mind to chemical pursuits ; that he had 

 made an experiment to ascertain the difficulty of raising oil 

 above a certain degree, with a particular portion of fuel, and to 

 do this, I took,*' said he, " a small portion of oil, and heated 

 it in a vessel over an Argand lamp : I found I could easily raise 

 it to 400°, but I could go no further with that degree of heat." 



Henry Coxwell, Esq., one of the chairmen of the com- 

 mittee of chemistry at the Society of Arts, was next called. 

 This gentleman gave it as his decided opinion that the opera- 

 tion of boiling sugar by the oil process, is infinitely less hazard- 

 ous than the common mode, and that he considered it to be so 

 for the reasons already given by Mr. William Allen and others, 



Mr. James Deville, manufacturer of gas-light- apparatus, 

 stated, that '* he had been much accustomed to the uses of oil 

 and experiments connected with it ; that he had been in sugar- 

 houses in great number, and thought, for the reasons already 

 given, that the oil method was safer than the old mode ; that 

 in an experiment he made with oil he took the degrees of tem- 

 perature every two minutes and a half,— that at first he in- 

 creased it 27° in that time, then only 18°, and afterwards only 

 in the following ratio, 15°~ 12°— .10°— 8°— 6°, of heat acquired 

 in the same time, though the fire became still stronger and 



