Mineralogy. ixxxiii 
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Protoxide of iron.......... 04°00 
AIRGAS. oa son sins. Xs oinetia 13:00 
Oxide of titanium........ > teat ud 
Protoxide of manganese.... 5°15 
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99-07 
Professor Pfaff has observed that there is a striking resem- 
blance between zirconia and the oxide of titanium. ‘To prove 
this he has drawn up the following table: 
(1.) Zirconia and oxide of titanium are both insoluble in 
caustic alkalies. 
(2.) Both are somewhat soluble in carbonates of potash and 
soda. 
(3.) The solution of zirconia in muriatic acid, when heated | 
to a certain temperature, becomes milk white, and runs in some 
measure into a jelly, especially if it has been concentrated to a 
certain point by evaporation. The muriatic solution of oxide of 
titanium exhibits the same appearances. 
(4.) From the muriatic solution of zirconia, oxalic acid throws 
down a white precipitate, which is again re-dissolved by an ex- 
cess of the acid. This is the case also with the solution of 
oxide of titanium. 
(5.) Zirconia and oxide of titanium are precipitated from their 
acid solutions by the neutral succinates and benzoates in copi- 
ous white bulky flocks, which are again readily dissolved by the 
addition of succinic acid. 
(6.) Tartaric acid, or tartrate of potash, occasions a precipi- 
tate when dropt into the solution either of zirconia or oxide of 
titanium. euthe 
(7.) Malic acid produces, in ‘both solutions, a copious white 
precipitate. ; 
' (8.) Prussiate of potash throws down a green precipitate in 
the common solution of oxide of titanium; which, by a certain 
‘increase in the oxidation of' the titanium, becomes almost quite 
blue. From a moderately neutral muriatic solution of zirconia 
prussiate of potash throws down a greenish blue precipitate, 
which, on the addition of muriatic acid, becomes more blue ; 
but, after a certain interval of time, changes into celadon green. 
The liquid above both precipitates remains. of the same green 
colour. i 
(9.) Hydrosulphuret of ammonia produces, in the muriatic 
acid solution of oxide of titanium, a dark olive or blackish green 
precipitate in very loose flocks. This precipitate. may be washed 
without any loss of colour; but when exposed to sunshine it 
becomes quite white. The same phenomena take place when 
