360 On the Chemical Evidence 



limpid oil is, the more it will transmit heat. It has been proved 

 by Count Rumford, and other chemists, that the transmission of 

 heat is retarded by its being solid/' 



Observations. — I conceive that Mr. Aikin ought not to have 

 dilated upon the effects which would take place when whale oil 

 was " boiled pretty rapidly ;" because it had been proved in 

 court, that the oil which was employed for heating the sugar at 

 Whitechapel was never boiled y but heated only to a temperature 

 of about 340°, or 350°. In regard to Dippel's oil, I am surprised 

 Mr. Aikin did not know that this substance cannot be produced 

 by any means but by what has been called destructive distilla- 

 tion. His observations respecting the thermometer do not ex- 

 actly apply, because there would be no difficulty in placing a 

 thermometer so that the bulb should touch the bottom of the 

 vessel. I think Mr. Aikin was wrong in saying, that to procure 

 inflammable vapour from oil it would require " a temperature 

 sufficient to char the substance," for several persons have 

 proved that they had produced it at a much lower temperature 

 than this indicates ; but if Mr. Aikin had said inflammable gas, 

 I could agree with him entirely. 



Mr. Aikin is, I think, perfectly right in the importance which 

 he attaches to the pump in this apparatus ; and his opinion of 

 the superior quality of southern whale-oil, in some measure 

 justifies Messrs. Severns in having chosen that particular kind 

 for their purpose of boiling sugar. The opinions of Count Rum* 

 ford respecting the power which fluids have of conducting heat, 

 are not at this day entirely agreed to, but I believe Mr. Aikin is 

 quite right in his conclusions on this part of the subject. 



Several witnesses were now called to give evidence respecting 

 their observations on the first appearance of the fire, and they 

 each declared that the flames were of the usual colour, and that 

 they perceived no peculiar smell whatever. 



On tl^e Third Day of the trial Mr. Faraday was recalled, 

 and he delivered the following opinions : That the vapour given 

 out frpm the oil-yessel at the sugar-hpuse, " if fired, would 



