52 Mr. T. J. Pearsall on the 



When nitrate of silver was added to this crimson solution, 

 an abundant white precipitate of oxalate of silver was pro- 

 duced, which was readily soluble in diluted nitric acid, and 

 thus easily distinguished from the chloride of silver, for which 

 it might be mistaken from its similar appearance ; more espe- 

 cially as the oxalate, like the chloride of silver, is soluble in 

 pure ammonia. 



Hence it appears that these red solutions possessed bleach- 

 ing powers in consequence of the peculiar state of manganese, 

 and independent of chlorine *. 



When pink or crimson solutions of manganese, supposed to 

 contain red, deut, or peroxide, were compared with solutions 

 known to contain manganesic acid, their similarity in some 

 properties was so striking, that I was induced to suspect that 

 manganesic acid alone ought to be regarded as the cause of the 

 peculiar effects. 



1. The varieties of scarlet, crimson, or purple colours 

 belonging to manganesic acid, in different circumstances, may 

 be imitated by those from sulphuric acid and oxides of man- 

 ganese. 2. The red solutions of oxides are always very 

 acid; manganesic acid is soluble and compatible with acids. 

 3. The red solutions by oxides and sulphuric acid bleach ; 

 manganesic and sulphuric acids, mixed, also bleach very 

 strongly. 4. The crimson solution by the action of bin- 

 oxalates upon oxides of manganese bleaches indigo ; man- 

 ganesate of potassa with binoxalates also does the same. 

 5. Both kinds of solutions are alike rendered colourless by 

 the same deoxidizing agents. 6. Both kinds of solutions 

 are subject to decomposition by mere dilution with water. 

 7. The sulphuric solution evolves a peculiar odour ; manga- 

 nesic acid in vapour has a similar odour. 8. The addition of 

 certain metallic salts to the supposed solutions of oxides, and 

 also to solutions holding manganesic acid, give similar appear- 

 ances ; and indeed the similarity of the two sets of compared 



* Mac Mullen on the Native Black Oxide of Manganese Quarterly Journal of 

 Science, xxii. 233, xxiv. 261. Phillip's Observations on Mac Mullen Annals 

 of Phil., and Phil. Mag. N. S.,i., 313. F. W. Johnstone on the Evolution of 

 Chlorine from the artificial Oxides of Manganese Quarterly Journal of Science, 

 xxv. p. 154. Kane on Existence of Chlorine in Peroxide of Manganese, Ibid., 

 p. 286. 



