338 On the Chemical Evidence 



whether a certain quantity of common oil, mixed with that oil 

 which had been boiled, would produce inflammable vapour at a 

 low temperature. The vapour did not appear inflammable 

 until we came to a temperature of 280°. The vapour at 280° 

 took fire in sudden gusts, as an explosion ; when it came to a 

 temperature between 280° and 300°, there was a noise like fat 

 frying in the boiler ; and when the vapour that was inflammable 

 issued from the tube, there was a sudden concussion in the 

 boiler, which I call an explosion. On the 16th of February, I 

 emptied the boiler and cleaned it out, and then put in about 

 thirty-three gallons of fresh whale-oil. The experiment was 

 continued twelve days, and the oil was heated about eleven 

 hours each day, and the highest to which it was carried was 

 507°. On the second day the vapour was slightly inflammable 

 at 375°, as it was before at 280°, in the other oil. On the 

 fourth day the vapour was very inflammable at 360°, and at 

 380° scarcely inflammable. On the sixth day I applied a light 

 to the vapour in the holler , which took fire. I unscrewed the 

 tube, and applied a light to the hole in the boiler, and the 

 vapour burned in the boiler. On the seventh day i I was sug- 

 gested that it was proper to take twelve gallons of ilie oil out 

 of the boiler, which was done. I received orders at the same 

 time to raise the temperature to 500°. On the eighth day it 

 was carried to 500° ; when at the highest it was inflammable at 

 seven inches and a half from the top of the tube, and it burned 

 like lightning ; the explosion in the boiler was still the same. 

 When this concussion did not take place in the boiler, there 

 was no vapour or flame, it was only fire occasionally, as the 

 vapour came from the tube. On the ninth day, at 497°, the 

 vapour took fire at the end of the worm : there was a worm 

 attached to the boiler by another pipe; this was fifteen feet 

 long, it passed through a cask of water, and at the end of this 

 it took fire at 497°, and continued burning twenty minutes, and 

 burned six inches in length. On the tenth day it was inflam- 

 mable at 345° ; at 390° it spread itself like lightning. On the 

 eleventh and twelfth days it was slightly inflammable at 310°. 

 Mr. Pastorelli supplied the thermometer, I received it from him 



