Combustible Substances. 172 



differs little from ordinary ardent spirits; it is only 

 more free from water. Soon after, a very subtile, 

 volatile, penetrating fluid rises from the mixture, 

 and a grateful aromatic odour spreads through 

 the room : this fluid is called SULPHURIC ETHER. 

 We know when it begins to rise by the striae 

 formed on the upper part and neck of the retort. 

 When about one third of the mixture is come 

 over, a viscid matter begins to rise. Here the 

 receiver, containing the ether, must be removed, 

 and another fixed to the retort ; for the matter 

 which then rises would render the ether impure. 

 When this process has been carried on too far, a 

 part of the sulphurous acid comes over, which has 

 a disagreeable smell, like that proceeding from 

 sulphur and bitumen. When the acid comes 

 over, it generally gives a moistness to the air. 



It is difficult to carry on the process further, 

 on account of the black fumes which rise, and 

 which by their expansion burst the vessels. The 

 mixture, when first put into the retort, has little 

 colour ; but during the process it changes, first 

 into a yellow, then brown, then black, and be- 

 comes viscid. Large bubbles arise, as in tar. 

 In this state it has a very nauseous smell. If 

 curiosity leads us to extend the experiment fur- 

 ther, we must proceed with a gentler heat, and 

 thus there arises more of the sulphurous acid and 

 water ; at last there remains in the retort a sul- 

 phurous carbonaceous matter. 



2. ETHER is the lightest of all fluids, for it 



VOL. II. L 



