328 On the Chemical Evidence 



perature, at which an inflammable gas is given out from oil that 

 had been heated repeatedly : that having mixed fifteen ounces 

 of sugar with five ounces of water, and heated the mixture in a 

 small copper-vessel, the following appearances were observed : 

 — When the sugar and water had acquired the temperature of 

 230°, the mixture boiled rapidly ; this it continued to do for 

 about an hour, and during that time the thermometer remained 

 stationary. Afterwards, as the water evaporated, the mercury 

 moved slowly upwards until it marked 343°, when the sugar 

 became black. The heat was continued until the temperature 

 arrived at 370°, and then the sugar burnt with a very strong and 

 permanent flame, and at length what remained in the pan be- 

 came carbonized like a coke. In answer to some questions re- 

 specting an experiment on oil, I stated, that having heated five 

 quarts of oil, it was found that when the oil acquired the tem- 

 perature of 350° a vapour arose from it, but this was aqueous 

 and not inflammable ; that this uninflammable vapour continued 

 to be given out until the thermometer rose to nearly 590°, 

 and then an inflammable vapour was perceived; but it was a 

 very feeble lambent flame, and the moment the lighted match 

 was withdrawn, the flame went out. Having been asked 

 whether it would be easy by mere negligence in attending the 

 fire under the oil-vessel, to bring the oil up to a temperature of 

 600°, and the court having inquired of Mr. Wilson the size of 

 the vessel, and he having stated that it was nine feet long, 

 three feet wide and eighteen inches deep, and the size of the 

 fire-place from twenty to twenty-four inches wide ; I gave it as 

 my opinion that one fire, made in such a fire-place and under 

 such a vessel, could not have produced that effect, and that I 

 could not conceive how the working of the oil apparatus could 

 .possibly have occasioned the fire *. 



riments were commenced too short a time before the trial, to afford an op- 

 portunity for investigating every question that might arise upon the subject. 

 See the preceding observations on Mr. Wilson's evidence page 322. 



* In saying this, I meant it to be understood while the oil vessel and its 

 appendages remained perfect ^ and there is no evidence that they had sus- 

 tained any injury previous to the commencement of the fire. 



