80 Professor Graham's Chemical Report on the 



it ; and instances could be given of olive-oil igniting upon sawdust ; 

 of greasy rags from butter, heaped together, taking fire within a 

 period of twenty-four hours ; of the spontaneous combustion of tape- 

 measures, which are covered with an oil varnish, when heaped to- 

 gether, and even of an oil-skin umbrella put aside in a damp state. 

 The ignition of such materials has been often observed to be greatly 

 favoured by a slight warmth, such as the heat of the sun. I am 

 also informed by Mr Braidwood, that the great proportion of fires at 

 railway stations have originated in the lamp-store, and that in coach- 

 works also, when the fire can be traced, it is most frequently to the 

 painter's department, the fire having arisen spontaneously from the 

 ignition of oily matters. Lamp-black and ground charcoal are still 

 more inflammable, when the smallest quantity of oil obtains access 

 to them, and should not be admitted at all among ship's stores. 



The stowing metallic cans or stoneware jars of either oil or tur- 

 pentine in a warm place, is also attended with a danger which is less 

 obvious, namely, the starting of the corks of the vessels, or the actual 

 bursting of them by the great expansion of the liquid oil, which is 

 caused by heat. These liquids expand in volume so much as one 

 upon thirty, by a rise of not more than 60° of temperature, or by 

 such a change as from the ordinary low temperature of 40° to a blood 

 heat ; the latter temperature may easily be exceeded in an engine- 

 room. It is remarkable that the burning a few years ago of a large 

 steamer on the American lakes, which even surpassed in its fatality 

 the loss of the Amazon, was occasioned by the bursting, in the man- 

 ner described, of a jar of turpentine placed upon deck too close to the 

 funnel, by a party of journeymen painters who were passengers. 

 This steamer was also on her first voyage, and being newly varnish- 

 ed, the flames spread over her bulwarks and extended the whole 

 length of the vessel in a few minutes. 



The bulk-heads of coal-holds appear to admit of obtaining con- 

 siderable security from fire by being constructed double where close 

 to the boiler, with a sheet of air between the two partitions. The 

 tendency of coals to spontaneous ignition is increased by a moderate 

 heat, such as that of the engine-room, from which they would be pro- 

 tected by the double partition. I have obtained instances where 

 coals took fire in a factory, on two different occasions, by being heap- 

 ed for a length of time against a heated wall, of which the tempera- 

 ture could be supported by the hand ; also of coals igniting after some 

 days upon stone flags covering a flue, of which the temperature was 

 not known to rise above 150°, and of coals shewing indications of 

 taking fire by being thrown in bulk over a steam-pipe. These were 

 Lancashire coals, which are highly sulphureous ; but the same ac- 

 cident occurred with Wallsend coals, at the Chartered East Com- 

 pany's Works in London, where the coals were twice ignited through 

 a two-feet brick wall, of which the temperature was believed by Mr 

 Croll not to exceed 120° or 140 c . 



