200 
ME. N. STOEY-MASKELYNE ON THE 
kept for some time warm. Hydrogen disodium phosphate gave a very slight flocculent 
turbidity to the filtrate from that precipitate, but it had not the appearance of the mag- 
nesium salt. 
The interior of the portion of the tube drawn out and kept cool at the bend by a 
cooling-mixture was lined by a slightly yellowish-white sublimate. 
This white body was treated with hydrogen chloride, in which it was at first some- 
what difficult of solution, and was added to the water into which the chlorine had been 
passed. That liquid, which was acid in its reaction, was evaporated down as a clear solu- 
tion till it had become but a few drops, and barium chloride was added to it. A preci- 
pitate of barium sulphate was formed, which after some time was filtered off and weighed. 
It weighed (MJ008 grm. There can be no doubt, therefore, that Osbornite contains sulphur 
as an important constituent. The excess of barium was removed and ammonia added, 
which threw down a very decided flocculent nearly white precipitate. The filtrate from 
this precipitate left no visible residue on evaporation. The precipitate itself readily 
redissolved in hydrogen chloride, and was again reprecipitated by ammonia ; it resem- 
bled alumina in appearance, but it proved to be entirely insoluble in potash. The 
experiment, more than once repeated, of redissolving and reprecipitating it, as before, 
invariably gave a body insoluble in potash. 
Dissolved again in acid and all excess of the acid having been removed, the addition 
of sodium hyposulphite produced, on warming it, a white precipitate. Restored to its 
former condition of as nearly neutral a solution as possible, on being treated by an ex- 
cess of potassium sulphate, it gave a white precipitate. 
The insolubility of the ammonia-precipitate in caustic potash having pointed to the 
probability that either titanium or zirconium oxide was present, some preliminary com- 
parative experiments were made which led to the following method. 
Three small glass tubes, similar in all respects, were taken, and into one a portion of 
the precipitate formed hy ammonia from the Osbornite was transferred; into a second 
a quantity to appearance rather less of titanium oxide, formed in a similar manner by so- 
lution in acid and reprecipitation by ammonia, was put ; and the third was similarly 
charged with zirconium oxide, formed in as similar a manner as possible by passing chlo- 
rine over a heated mixture of zirconia and charcoal, and treating the sublimate as the 
mineral sublimate had been treated*. 
Hydrogen chloride and water were next added in equal amounts to each tube. A 
minute bit of magnesium wire was dropped into each, and the changes were watched 
under the microscope with an inch objective. After a certain period black patches 
began to appear on the magnesium wire in the titanium oxide tube, and a bluish colora- 
tion could be faintly discerned : in the tube with the precipitate from the Osbornite the 
magnesium retained its silvery brightness entirely unstained, as did the wire in the zirconia 
* It is remarkable that in this experiment the same internal iridescence of the glass tube was observed as 
in the experiment with the mineral, and the chloride sublimed in the same manner and with the same appear- 
ance. 
