Red Solutions of Manganese. 53 



solutions is so great as to offer the highest probability that their 

 powers depend upon a common cause. 



It will now be my endeavour to place clearly the experi- 

 mental reasoning which supports this new view of these solu- 

 tions; and, as the bleaching properties of the ordinary red 

 solutions has been first brought into consideration, I will show 

 that the same effects maybe produced by manganesic acid under 

 the same circumstances. 



A solution of manganesic acid in sulphuric acid was mode- 

 rately heated in a retort ; the portion distilled over did not 

 bleach, but the fluid, still red, bleached indigo instantly. If 

 much sulphuric acid be present, the mixture may in this expe- 

 riment be heated for some time, and sustain an elevated tem- 

 perature before the separation of oxide. 



Sulphuric acid was added to chamelion mineral, and pro- 

 duced a deep crimson solution of the red manganesate of 

 potassa, that instantly bleached a strong solution of indigo. 

 This red fluid heated in a retort evolved volatile matter, which 

 destroyed the blue colour ; but there was no trace of chlorine 

 in the bleached portions of indigo when tested by nitrate of 

 silver. 



These experiments with the sulphuric acid fluids containing 

 manganesic acid, prove that this state of manganese produces 

 the same results as the crimson solution. That the sulphuric 

 aeid was not essential to these effects was thus shown : by dis- 

 solving mineral chamelion in water it gave a deep green solu- 

 tion, which, when boiled, became deep red, and then bleached 

 sulphate of indigo ; the resulting fluid was unchanged by 

 nitrate of silver : an aqueous solution of manganesic acid pro- 

 duced the same effect. 



The crimson solution obtained by the alkaline binoxalate 

 and oxides of manganese is the only other particularly pointed 

 out as supposed to contain the deutoxide of manganese ; 

 although acid, it is not so strongly acid as the sulphuric fluid : 

 on adding oxalic acid or binoxalate of potassa to solution of 

 green chamelion, the rich colours of manganesic acid ap- 

 peared. This deep crimson solution is almost identical in 

 colour with the solution in the former oxalic experiment, and, 

 like it, also bleaches indigo. 



