1613<3 a Chemical Knowledge of Manganese. 175 



sists in the difficulty of uniting into a button the particles of it 

 after they are reduced into the metallic state. 



Gahn'sand Bergman's method of performing thereduction of 

 the metal in a crucible lined with charcoal, is, as I have satisfied 

 myself, the only one that succeeds. But in order to be free 

 from the inconveniency of either procuring imperfect grains, or 

 of obtaining them exceedingly small, some contrivances are 

 necessary, with which Oiese chemists were unacquainted, and 

 upon which the success of the experiment entirely depends. 



I repeated this difficult experiment more than ten times before 

 I obtained a result not merely accidentally successful, but 

 which constantly turns outthe same after the same preparation. 



Whether manganese reduced by means of charcoal be in a 

 state, chemically speaking, pure, is a question that remains to 

 be answered; but before I state my doubts on the subject, I shall 



f've a description of the method of reducing' manganese, which 

 found successful. 



I lined a Hessian crucible somewhat more than six inches 

 high within, with a paste composed of a small quantity of clay 

 mixed with precipitated silica, a great proportion of charcoal, 

 and the requisite quantity of water. The paste was laid on to 

 the thickness of half an inch every where, except at the bottom 

 where it was thicker. I now with my hands forced in as much 

 charcoal into the wet mass as the crucible would take up, leavino- 

 a conical hole in the middle, dried the crucible for some days in 

 a moderate warmth, and then heated it thoroughly red-hot. 



I heated the carbonated oxide, destined foAhe experiment 

 during an hour in a covered crucible, in order to drive off the 

 carbonic acid, and rubbed the light brown oxide obtained with 

 u.J to a paste. I then destroyed the oil by the application of a 

 moderate heat. This process the object of which was to mix 

 the oxide intimately with the charcoal of the oil, I repeated once 

 more. At last I rubbed to a fine powder the oxide thus treated 

 with oil, and reduced it with as little oil as possible in a mortar 

 to a firm mass. 1 his I formed into the shape of the cavity in 

 toe crucible, into which I introduced it, and filled up all the 

 interval with charcoal powder. The whole was then exposed to 

 a mock-rate heat fbr half an hour. A cover was now put upon 

 toe crucible; U was placed among burning coals, in order to be 

 heated equably and gradually. Then it was suddenly exposed for 

 an hour and a hall' to as strong a fire as the crucible could be t -r 

 without melting. 



this process I obtained from 830 grains of carbonated 

 grains ofthepure metal; so that the loss, as will ap- 

 ■ from what follow.., was very small; and in experiments of 

 this uuture some loss is not to be avoided. 



