from the River Dee, in Aberdeenshire* 103 



II. Iserine, 



The colour of this ore is iron-black, with a shade of 

 brown. ' It consists of small angular grains, rather larger 

 than those of the iron-sand, but very similar to them in 

 their appearance. Their edges are blunt ) they are smoother^ 

 and have a stronger glimmering lustre than those of the 

 iron-sand. Lustre semi-metallic, inclining to metallic. 

 The fracture could not be distinctly observed, but it seemed 

 to be conchoidal ; at least nothing resembling a foliated 

 fracture could be perceived. Opake, semi-hard, brittle, 

 easily reduced to powder; colour of the powder unaltered; 

 specific gravity 4*491 *; scarcely attracted by the magnet. 



1. A hundred grains of the powdered ore were mixed 

 with six times their weight of carbonate of soda, and ex- 

 posed for two hours to a red heat, in a platinum crucible. 

 The mass obtained, being softened with water, dissolved 

 completely in muriatic acid. When the solution was con- 

 centrated, it assumed the appearance of the yolk of an egg. 

 It was boiled, diluted with water, and set aside for some 

 time. A white matter gradually deposited, which, when 

 dried on the steam-bath, weighed 53 grains, and possessed 

 the properties of oxide of titanium. 



2. The liquid thus freed from titanium was evaporated 

 to dryness, and the residue redissolved in water, acidulated 

 with muriatic acid. A white powder remained, which, 

 after being heated to redness, weighed 16' 8 grains, and 

 possessed the properties of silica. 



3. The solution was precipitated by ammonia, and the 

 brown matter which had separated, boiled for some time in 

 liquid potash. The whole was then thrown on a filter, to 

 separate the undissolved part, and the liquid which came 

 through was mixed with a solution of sal-ammoniac. A 

 white powder fell, which, after being heated to redness, 

 weighed 3*2 grains. It was alumina. 



4. The brown substance collected on the filter was dried, 

 drenched in oil, and heated to redness. It was strongly 

 attracted by the magnet, and weighed 52 grains. 



5. It was digested in diluted sulphuric acid; but not 

 being rapidly acted upon, a quantity of muriatic acid was 

 added, and the digestion continued. The whole slowly 

 dissolved, except a blackish matter, which became white 

 when exposed to a red heat, and, as far as I could judge 



* If, as the following analysis would lead us to expect, the specimen ex- 

 amined was a mixture of four parts iserine, and one part quartz and felspar, 

 the specific gravity of pure iserine should be 4i)6"4. - 



G 4 from 



