76 ESSAY V. 



solution of this earth in nitrous or muriatic acids is not 

 precipitated either by phosphoric, tartar, or fluor acid, 

 though it is by all ammoniacal salts containing these 

 acids, (h) This solution is precipitated by vitriolic acid, 

 and the precipitate is insoluble in water (Sees. IV. (&), vi. (c)). 

 It is likewise precipitated by vitriolated vegetable, fossil, 

 volatile alkalies, and lime ; as also by iron, copper, and 

 zinc, combined with the same acid. (i) The vitriolic 

 acid is not separable from this earth, either by alkali, 

 lime, or solution of silver or quicksilver. The only means to 

 effect this separation is to convert the acid into sulphur. 

 This may be done by mixing the edulcorated precipitate 

 with alkali of tartar and a little charcoal powder, fusing 

 the mixture, afterwards dissolving the mass in water, 

 and edulcorating the powder that lies at the bottom, 

 which then may be again dissolved in nitrous acid, and 

 thus purified from the charcoal, (k) By fusing it with 

 black flux and powder of charcoal I obtained no metallic 

 substance. 



Hence it appears that' this earth differs from all other 

 earths hitherto known. But I am also convinced, from 

 experiments, that this earth is not found in manganese 

 alone: for, when you lixiviate potashes made of trees, 

 or other smaller vegetables, in order to free them from 

 vitriolated tartar, and afterwards dissolve them in pure 

 nitrous or muriatic acid, filter the solution, and dilute it 

 with water ; then, on pouring into it some drops of 

 vitriolic acid, you obtain, in a quarter of an hour's time, 

 a fine white precipitate, which consists of this earth and 

 vitriolic acid, and is exactly the same with the precipitate 

 of (b). 



