SPONTANEOUS COMBUSTION. 313 



LETTER XIII. 



Spontaneous combustion In the absorption of air by 

 powdered charcoal and of hydrogen by spongy platinum 

 Dobereiner's lamp Spontaneous combustion in the 

 bowels of the earth Burning cliffs Burning soil Com- 

 bustion without flame Spontaneous combustion of human 

 beings Countess Zangari Grace Pett Natural fire- 

 temples of the Guebres Spontaneous fires in the Caspian 

 Sea Springs of inflammable gas near Glasgow Natural 

 light-house of Maracaybo New elastic fluids in their 

 cavities of gems Chemical operation going on in their 

 cavities Explosions produced in them by heat Re- 

 markable changes of colour from chemical causes 

 Effects of the nitrous oxide of Paradise gas when, 

 breathed Remarkable cases described Conclusion. 



AMONG the wonderful phenomena which chemis- 

 try presents to us, there are few more remarkable 

 than those of spontaneous combustion, in which 

 bodies both animate and inanimate emit flames, 

 and are sometimes entirely consumed by internal 

 fire. One of the commonest experiments in 

 chemistry is that of producing inflammation by 

 mixing two fluids perfectly cold. Becker, we 

 believe, was the first person who discovered that 

 this singular effect was produced by mixing oil 

 of vitriol with oil of turpentine. Borrichios 

 showed that aqua-fortis produced the same effect 

 as oil of vitriol. Tournefort proved that spirit of 

 nitre and oil of sassafras took fire when mixed ; 

 and Homberg discovered that the same property 



