1 14 Mr. R. H. Brett and Mr. Golding Bird on the 



forms of titaniferous sand we at first were inclined to believe 

 the presence of titanium was owing, this opinion appearing to 

 be corroborated by our noticing that in those crucibles in 

 which the black specks (above referred to) were most nu- 

 merous, the quantity of titanium appeared to be the greatest. 

 The source of that metal in these crucibles must still remain a 

 question. 



We subjoin an outline of the process we followed in the 

 analysis of these crucibles, as we believe that the (hitherto 

 unlooked for) presence of titanium in these articles of che- 

 mical research to be of some importance in analytical che- 

 mistry. 



1. A portion of a crucible was reduced to fine powder in 

 an agate mortar, then carefully mingled with three times its 

 weight of carbonate of potass in a platinum crucible; the lat- 

 ter was then exposed to a red heat until all effervescence had 

 ceased ; the heat was then raised to whiteness so as to ensure 

 perfect decomposition of the silicious body. The fused mass 

 while hot was yellow; on cooling, however, it became greyish 

 and opake. 



2. The crucible being wiped from the adhering ashes was 

 placed in a glass cylinder, covered with distilled water ; hy- 

 drochloric acid was then poured in and the cylinder closed 

 with a watch-glass. After some hours the fused mass was en- 

 tirely dissolved or loosened out of the crucible ; the latter was 

 removed, rinsed with distilled water, the washings being 

 added to the solution, which was nearly limpid, (a few light 

 flakes of silicic acid were in suspension,) a little nitric acid was 

 added, and the whole evaporated to dryness ; the residue was 

 diffused through a considerable quantity of distilled water and 

 thrown oji a filter: the silicic acid thus separated was washed 

 with distilled water until the last portions of fluid ceased to 

 affect nitrate of silver ; it was then dried, ignited, and weighed. 



3. The filtered liquor with the washings was evaporated 

 over a steam-bath to half a pint, a few grains of sugar added 

 (to reduce the manganese to protoxide and thus render it so- 

 luble in an ammoniacal salt), and ammonia poured in to super- 

 saturation: a copious gelatinous precipitate fell, which was 

 collected on a filter, washed with a dilute solution of muriate 

 of ammonia, and thoroughly dried on a sand-bath. 



4. The dried precipitate thus obtained, consisting of titanic 

 acid, alumina, and peroxide of iron, was boiled in hydrochlo- 

 ric acid, which dissolved the alumina and iron ; the insoluble 

 titanic acid was then washed, ignited, and weighed. 



5. The acid solution of alumina and iron was mixed with 

 an excess of caustic potass and boiled: the peroxide of iron 

 thus separated was then ignited and weighed. 



