EXPLOSIBILITY OF COAL OILS. 335 



finally did, at degrees of temperature varying from 80° to 162°, ex- 

 hibiting faint flames quivering over the surface of the oil, precisely 

 like those hovering over the surface of spirits of wine or alcohol 

 when similarly kindled. The flames were quite as readily extin- 

 guished by a blast of the breath, and not the least symptom of any 

 explosive character became manifest when each one took fire. Until 

 the evaporative point of each sample of oil was produced by the in- 

 crease of heat applied, and until lambent flames were kindled, burn- 

 ing matches were extinguished when plunged into the coal oil, as 

 effectually as if they had been similarly plunged into water. The 

 average heat at which all the samples emitted sufficient vapor to 

 admit of being kindled was about 125^ of Fahrenheit's scale. 



After ascertaining the temperature requisite to kindle the several 

 samples of coal oil, it next becomes an interesting subject of investi- 

 gation to ascertain the heat to which coal oil is ordinarily elevated 

 whilst burning in lamps. The results of actual experiments showed 

 that in glass lamps the temperature is increased about 6°, and in 

 metallic lamps but 10° or 12°, above that of the apartment ; which, 

 being 67°, produced a heat in the oil of about 71° to 79°, leaving a 

 considerable range of temperature below the average of 125°, above 

 stated. 



Finding by actual observation that only the gaseous vapors arising 

 from the heated oil exhibit the phenomenon of flame whilst ascend- 

 ing, and combining chemically with the oxygen of the air, it became 

 manifest that no explosive action could be anticipated to take place 

 from any kind of oil or inflammable spirits, unless these gaseous vapors 

 were first evolved by a previous increase of temperature, and then 

 brought into contact with the atmospheric air before applying a match 

 thereto. There being no room left for either the gaseous vapor of 

 the oil or for atmospheric air to combine therewith, in the chamber 

 of any lamp entirely filled with oil, every attempt to produce explo- 

 sive action with a full lamp, at all temperatures up to the boiling 

 point of water, utterly failed when lighted matches were applied to 

 the open orifice of the lamp. The only result produced by increasing 

 the heat of the coal oil was an increase of the evaporation of the gas, 

 and a higher jet of flame steadily rising, as from the jet of a gas-burner. 

 So long as lamps are kept full of oil, or even of explosive camphene 

 and "burning fluid," there can be no explosive action whatever. 

 For this special reason it may be adopted as a safe rule to cause all 

 lamps containing highly imflammable liquids to be kept as full as prac- 

 ticable by being daily replenished. 



As nearly all the published accounts of the explosions of camphene 

 lamps, and of the consequent dangerous and frequently fatal conse- 

 quences that have ensued, represent the occurrences to take place 

 during the process of filHng them whilst empty, the chamber of the 

 lamp or of the feeder being then occupied by gaseous vapor com- 

 mingled with atmospheric air, an experiment was made with a glass 

 factory lamp under similar circumstances, as being favorable for ex- 

 hibiting the most violent explosive action producible by means of 

 coal oil. Accordingly a lighted match was plunged into the oj*ifice of 



