252 On the Composition of Arragonite. [Oct. 



brought to the consistence of a syrup with a portion of absolute 

 alcohol. This was thrown into a glass, and the capsule was washed 

 clean with alcohol. The glass was then kept agitated, and absolute 

 alcohol was gradually poured in till the powder was completely 

 dissolved. The solution thus formed was milky, and in 12 hours 

 deposited a white sediment, and became clear. The whole was 

 thrown upon a filter kept covered with a glass plate, and what 

 remained upon the filter was washed with alcohol. It exhibited the 

 properties of nitrate of strontian. 



The other half of the solution was (in order to verify the accuracy 

 of the process contrived by Bucholz, for his own trials were upon a 

 very small scale,) evaporated to dryness, and the dry mass exposed 

 to a red heat in a platinum crucible till the whole nitric acid was 

 decomposed. The residue was digested in boiling hot water in a 

 covered platinum crucible, the milky liquid was thrown upon a 

 covered filter, and what remained upon the filter was likewise 

 washed with hot water. The whole of this liquid solution, which 

 might amount to rather more than six ounces, being put into a 

 retort furnished with a receiver, was distilled down to the quantity 

 of 14- drams. Next morning small sandy crystals were visible upon 

 the sides and bottom of the retort. Unexpectedly there appeared, 

 half an hour after, a distinct, though small, groupe of plumose 

 crystals, obviously of strontian. Without waiting any longer, some 

 nitric acid was poured into the retort, and the solution was evapo- 

 rated to dryness. Even during the evaporation small crystals 

 separated, which, being kept, were washed with absolute alcohol in 

 the same manner as nitrate of lime, described above. 



Two solutions of columnar arragonite from Auvergne, each of 200 

 grains, were treated exactly in the same manner. In these experi- 

 ments the strontian did not crystallize so soon as in the preceding ; 

 but it showed itself in the same manner when the retort was washed 

 with nitric acid, and when the solution was treated in the way 

 before described. 



Thus is the discovery of Stromeyer confirmed ; and thereby a 

 dispute, long carried on, finally settled. It shows us that between 

 two branches of the same science not a single discrepancy exists ; 

 and that when any such makes its appearance, it is not necessary 

 for us to modify the principles of either the one branch or the 

 other; for we may be certain that the discrepancy will finally dis- 

 appear by the discovery of some ingredient hitherto overlooked. In 

 respect of chemistry, in particular, it shows us that we must 

 have recourse to all the aids with which the science furnishes us : 

 and that though the analysis has sometimes to struggle with great 

 difficulties, it does not finally forsake us. 



There still exists a similar discrepancy between chemistry and 

 oryctography, in respect of the anatase and rutil ; but these mine- 

 rals, unless I deceive myself, contain the titanium which is common 

 10 both in different states of oxidation ; and there is the same 

 difference between them as exists between those ores of iron which 



