at Ltmmgton Priors. 261 



ptiiffiat of pot-afh. Every chalybeat fprlng may be fuf- 

 pe£t,ed to contain fome manganefe likewife ; and fhould 

 therefore be examined accordingly. 



VI. TESTS OF MANGANESE AND IRON. ' 



As I (hall have frequent occafion to mention this mix- 

 ture of.oxydes of manganefe and iron, I will enumerate -the 

 teds I have ufed, to avoid ufelefs repetitions. Thefe are, 1. 

 The magnet: to this the fmalleft particle of iron may be 

 rendered obedient, by expofing it to a due heat, on char- 

 coal, by the blow-pipe. 2. The tinge communicated by 

 the procefs to a globule of borax : this from iron is green or 

 yellow; from manganefe it is hyacinthine ; or, when the 

 globule is more loaded with the metal, a fine rich red. This 

 colour difappears by the blue conical flame; and maybe 

 re-produced by the gentler yellow flame which funounds 

 the cone. 3. Fufion with nitre, or with carbonate of foda : 

 manganefe imparts to them a fine blue colour ; but if it be 

 mixed with the oxyde of iron the colour is green. 



VII. AN HTPOTHESIS TO EXPLAIN THE CAUSE OF THE 

 PHENOMENA. 



The firfl hypothefis which I framed, to account for the 

 £a£b in queflion, was deduced from the well-known pro- 

 perty which manganefe pofTefTes of oxygenating the muriatic 

 acid. My rcafoning was as follows : — Since, during the 

 folution of the black oxyde of manganefe in the muriatic 

 acid, a portion of the acid becomes oxygenated, it mud fol- 

 low, that, if this portion Ihould meet and combine with a 

 metallic oxyde, the fait formed by fuch an union muft be 

 fuperoxygenated. But in the date of oxydation, doubtlefe, 

 is a great part of the iron which is fo abundantly diffufed 

 through the earth. Are then the appearances in queftion 

 the refult of thefe circumftances ? In fhort, are the falts 

 muriat of manganefe and oxygenated muriat of inn ? In 

 purfuance of this idea I formed fome oxygenated muriat of 

 S 3 iron, 



