360 Scientific Intelligence. 



As the kind of substances were almost the same as those in polymignite, 

 JDr Woehler followed nearly the same plan which Berzelius had adopted in 

 the analysis of that mineral. 



. In order to ascertain the quantity of volatile ingredients it was heated 

 in a glass tube, enlarging into a ball in its centre, over the argand spirit 

 lamp. Some only of the small fragments showed the phenomenon of in- 

 candescence like gadolinite, though they were all alike afterwards in ap- 

 pearance. Water and fluoric acid, to the extent of 4.2 per cent, were dis- 

 engaged. 



A. The mineral reduced to an impalpable powder was decomposed by 

 dilute sulphuric acid, with which it was digested for some time. A glass 

 plate, with which it was covered, became corroded by the disengagement 

 of fluoric acid. The pulpy mass, obtained by evaporating most of the wa- 

 ter, was white, only a little inclining to bluish-green. It was again 

 mixed with much water to precipitate entirely the titanic acid, and to dis- 

 solve the gypsum. 



B. The solution filtered off the white residue was precipitated by pure 

 ammonia. It yielded a pale brownish-yellow precipitate, which became 

 brown on being washed. The remaining fluid was precipitated with oxa- 

 late of ammonia. The oxalate of lime thus obtained was ignited, then 

 melted with carbonate of ammonia, and again slightly heated, to reduce 

 it to the state of carbonate. 



C. The liquid from which the lime had been precipitated, left, by eva- 

 poration, a residue which contained traees of magnesia, but principally 

 proved to consist of sulphate of manganese. 



D. The residue in A chiefly consisted of titanic acid. While yet in 

 its humid state it was digested in hydrosulphuret of ammonia, which im- 

 mediately turned leek-green, but so slightly, that the quantity of iron it 

 contained can be but very inconsiderable. The hepatic fluid evaporated, 

 Jeft a small quantity of a dirty yellowish powder, which allowed with 

 great facility globules of tin to be reduced before the blowpipe. The re- 

 maining powder was pure titanic acid, assuming a fine lemon-yellow tint 

 when heated, which it again lost on cooling. With salt of phosphorus it 

 gave the well known amethystine colour in the reducing flame, and with 

 soda an opaque globule, which disengaged much light on becoming solid. 

 It did not show any traces of silica, of tantalic acid, or of zirconia. 



E. The precipitate obtained in B by pure ammonia was digested in cau- 

 stic potash. The liquid thus obtained was supersaturated with muriatic 

 acid, but did not give any precipitate by ammonia. It contained, there- 

 fore, no alumina. 



The residue was digested in a concentrated solution of carbonate of am* 

 monia. Its brown tint became still darker, and the liquid assumed a yel- 

 low colour. This liquid filtered off, on being diluted with the washings of 

 the brown residue, became turbid, and a yellowish-white precipitate ap- 

 peared when it was heated to drive away the carbonate of ammonia. When 

 dried, it had a greyish-brown colour, and gave reactions only of tin and 

 cerium. 



The remaining yellow ammoniacal solution being evaporated to dry- 



