ON MANGANESE 93 



this I separated by filtration ; then diluted the solution with 

 6 oz. of distilled water, and precipitated it with purified 

 alkali of tartar ; but as in this process there is always a 

 certain quantity of aerial acid expelled from the alkali by 

 the acid, which may dissolve some manganese (Sec. XXXL), 

 it was necessary to place the whole mixture, with its 

 precipitate, in an open vessel upon hot sand, in order to 

 expel the aerial acid. In the space of a few hours it was 

 filtered, and what remained in the filter was edulcorated 

 with hot distilled water. This phlogisticated manganese was 

 afterwards dried, and exposed again to calcination in the 

 same manner. All this was done with proper care not to 

 lose anything ; on which account the draught of air was 

 carefully avoided. The manganese, when deprived of its 

 phlogiston, was again dissolved in diluted vitriolic acid, with 

 the addition of a little sugar, by which means I obtained as 

 much selenite as before ; the solution was then made to pass 

 through the same filter, on which the selenite remained 

 behind mixed with that of the preceding operation. The 

 filtered solution was precipitated by alkali of tartar, and, by 

 means of heat, deprived of the aerial acid ; it was afterwards 

 purified, as before, from the vitriolated tartar, by means of 

 the same filter, edulcorated, then dried, and again deprived 

 of its phlogiston by a new calcination. This operation I 

 repeated eleven times, till I grew tired of it. I dried the 

 phlogisticated manganese which was last obtained upon the 

 same blotting paper which had served as a filter, then, 

 subtracting the weight of this paper, which I had ascertained 

 before the experiments were begun, I found the weight of 

 the manganese to be 3 drms. and 5 grs., the selenite obtained 

 49 grs. It is impossible to avoid some loss in the edulcora- 

 tion. The phlogisticated manganese thus obtained had the 

 same property as in the beginning, and yielded, after the 



