Chlorine in Peroxide of Manganese. 289 



Mr. Mac Mullen next travels to the subject of chameleon 

 mineral, and entirely overturning by theory the facts of Che- 

 villot and Edwards, he says, that in their well-known experi- 

 ments the azote was absorbed, and prevented the formation of 

 chameleon mineral, not by excluding oxygen, but by forming 

 nitrate of manganese. From this explanation, Mr. Mac Mullen 

 infers that chameleon mineral is a chlorate of manganese and 

 potash, and supports his opinion by the inflammation of man- 

 ganesiate of potassa with combustibles. 



Wishing rather to increase the validity of the opinion of the 

 French chemists than to overturn that of Mr. Mac Mullen, I 

 made some experiments, which I will state in full. 



Exp. 1. Into a strong tube-retort, a small quantity of oxide 

 of manganese and pure potash was introduced, and rammed 

 tight by a copper wire. The open extremity was now drawn 

 out, like the neck of the receiver figured in Faraday's Manipu-' 

 lation^ p. 399. The retort was then filled at the mercurial 

 trough with nitrogen previously passed over dry chloride of 

 calcium, the capillary end was then strongly sealed. The body of 

 the retort being now coated with lute, was brought to redness, 

 and the heat increased until it began to soften ; it was then 

 removed, and the sealed end broken under mercury ; instead of 

 any absorption, a quantity of gaseous matter rushed out, which 

 I could not obtain for examination. In repeating this experi- 

 ment several times the tubes generally burst, unless they were 

 very thick, well sealed, and removed the instant they began to 

 soften. 



Exp, 2. The retort was charged, and the open end drawn 

 into a fine tube, which passed under a jar in the mercurial 

 trough ; a considerable quantity of gaseous matter was ob- 

 tained, and found to consist, the first portion of oxygen and the 

 nitrogen of the apparatus, the latter of pure oxygen. 



Exp. 3. The retort being charged with manganese and po- 

 tassa, was filled with oxygen at the mercurial trough, and 

 sealed ; the luted portion was brought to bright redness ; when 

 coated, the narrow end was broken under mercury, when a con- 

 siderable rise into the retort indicated the absorption of oxygen. 

 Mr. Mac Mullen states that the experiment, to insure success, 

 should be performed in vacuo. 1 had not a good air-pump, or 



