ON MANGANESE 65 



Mr. Rinman, though Mr. Westfeld looks upon it as a 

 constituent part of manganese. (2) Some siliceous earth is 

 likewise found mixed with manganese, but it does not enter 

 into the solution (Sec. II. (d)). That the siliceous earth is 

 not pure, appears from experiment ; but it may be obtained 

 quite pure by means of proper acids. (3) A little calcareous 

 earth, which, as far as I know, has not hitherto been taken 

 notice of. It is this with which the separated siliceous 

 earth is mixed (Sec. u. (d))', and, in consequence of its 

 absorbent nature, combining with the vitriolic acid, it forms 

 a neutral salt, which is soluble in water, and forms with 

 borax a brown glass (Sec. n. (d)), on account of the sulphur 

 produced during the fusion ; of which I shall speak more 

 particularly hereafter, Sec. xxxn. 



SECTION XIX. 



If the salt, consisting of vitriolic acid and manganese 

 (Sec. ii. (c)), be again dissolved in distilled water, and after- 

 wards crystallised, it will be obtained in a state of purity, 

 containing nothing of the admixtures mentioned in the 

 preceding paragraph. From it manganese, saturated with 

 phlogiston, may be precipitated by alkali of tartar. That 

 this manganese is really saturated with phlogiston appears 

 from this, that it cannot be united with more phlogiston, so 

 as to yield any metallic substance. If Mr. Westfeld had 

 examined this precipitate a little more, he certainly would not 

 have pronounced it to be the earth of alum. The earth 

 thus obtained is without the least particle of iron, and is 

 besides endowed with all the properties which mineralogists 

 ascribe to manganese, after the phlogiston has been separated 

 from it by calcination in the open air (Sec. xv. (c)). Thence 

 I infer that Mr. Westfeld's dissertation affords no instruction 

 whatsoever. 

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