348 THE ROYAL INSTITUTION. [CHAP. VI. 



Then he describes the alloys. 



4 The basis of potash, when thrown into the strong 

 mineral acids, inflames and burns on the surface.' 



Then he describes the effects with sulphuric acid, 

 and nitrous acid. 



' The action of the basis of potash on fat and volatile 

 oils, and on various bodies, is less violent than on any 

 other class of compound substances containing oxygen, 

 as might have been expected from the small quantity 

 of this principle which they hold in combination. 



' The application of naphtha to its preservation I 

 have already mentioned. On the colourless and per- 

 fectly transparent naphtha distilled from petroleum or 

 from brown naphtha at a low heat, and defended from 

 air, it has scarcely any action at common temperatures.' 



Then he describes the further action on naphtha. 

 'The fat and volatile oils closely related to naphtha 

 in composition resemble it likewise in their habitudes 

 with the basis of potash. The lightest naphtha that I 

 have been able to procure by double distillation was 

 of spec. gr. 770, water being 1,000, and was almost 

 colourless. In this fluid, confined in close vessels, the 

 globules swam for hours without apparently affecting 

 it, but by degrees a yellow film formed upon them, the 

 naphtha became brown at its point of contact, and the 

 globules sank to the bottom of the vessel. After 

 some days the fluid surrounding the globule appeared 

 black and turbid. 



' The fat and volatile oils approach to naphtha in their 

 habitudes with respect to the basis of potash. 



' The fat oils follow naphtha in the order of bodies 



