F.. W. Clarke on a new process in Mineral Analysis, 179 
assay is placed in the crucible, should take less than an hour to 
perform, 
This process has -a great advantage over all others, in the 
examination of ores, slags, and cinders containing iron, bot 
as regards speed and convenience, A perfectly clear solution 
is immediately obtained without filtering, all the silica is got 
rid of, and it is only necessary to reduce the iron with hydrogen, 
and then to titrate. If in an iron ore it is desited to determine 
titanic acid and manganese, it is best to make the subse- 
quent fusion with sulphuric acid. The clear solution obtained 
is diluted to a known quantity, and by means of a graduated’ 
pipette divided into several portions. In one part the iron ma 
be reduced and determined volumetrically; in another, the ti- 
tanic acid thrown down by boiling. In still another portion, 
the iron, alumina, and titanic acid may be thrown down by 
boiling with acetate of soda, and in the filtrate, the manganese 
may be precipitated by a current of chlorine gas, or by boiling 
with hypochlorite of soda. If fluorid of sodium be used in- 
stead of cryolite in the fusion, lime and magnesia also may be 
estimated. For determining silica, phosphorus, and sulphur, 
oe 
other methods must be employe 
trouble. Iron vessels are suitable for the operation, but must 
be very clean and free from rust. If caustic potassa be sub- 
stituted for soda, the deposit of fluorid of sodium is smaller, 
and the supernatant solution contains aluminate of potassa, 
fluorid of potassium, and a little fluorid of sodium. _ oe 
Possibly the fluorid of potassium might be prepared ina state 
purity from this solution, but it is) extremely pro lematical 
whether this could be done economically. When pure eryolite 
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