THE MINERALOGY OF SCOTLAND. 445 
sium bisulphate, and therewith fused. When cold the flux was dissolved in 
tartaric acid, made slightly alkaline with ammonia, and the iron separated by 
ammonium sulphide. 
The alumina and titanic acid, with the filtrate, were evaporated to dryness, 
ignited, burned white, and then mixed with concentrated sulphuric acid, in 
order to convert the sulphate of potash into bisulphate. 
After evaporation to dryness this was again fused; the enamel of the 
bisulphate of potash fusion was again dissolved, and it was then treated with 
an excess of caustic soda. This holds in solution the alumina completely, and 
leaves behind the insoluble titanate of soda. 
This titanate of soda was filtered off, ignited, and once more fused with 
potassium bisulphate ; from the solution of this, when diluted and boiled, all 
the titanic acid settles, although somewhat slowly. 
The alumina was separated from its solution in caustic soda by neutralisa- 
tion with acid, and reprecipitation by ammonia. The other parts of the process 
were those usually adopted. Though, from the number of fusions, very time- 
consuming, and though entailing somewhat more loss, this process was found 
to yield a slightly larger proportion of titanic acid than do any of the older 
processes, except the very tardy one with sulphuric acid ; and the perfect purity 
of the titanic acid seemed to be by it more assured. Unless there is abundance 
of material to operate on, a bisulphate fusion is however to be preferred, as the 
evaporation to dryness of the mass, after the addition of the sulphuric acid, was 
sometimes extremely troublesome. 
Tserine. 
It is singular that, although former writers on Scottish minerals do not 
notice ilmenite, they should in several instances have noted the occurrence of 
iserine,—sometimes under that name, sometimes as “magnetic iron sand,” 
and “black sand.” 
As before stated, however, they have sometimes confounded magnetite 
with true iserine; and they have also termed crystalline magnetite “ titanic 
iron.” 
The records which we have of the occurrence of iserine in Scotland are the 
following :—- 
“ On the bank of the Deveron, below the bridge of Macduff.” 
“On the shore of Canna.” . 
“Titanic iron with hornblende on Carrick Common, in Roxburgh.” 
