1813.] a Chemical Knowledge of Manganese. 269 



examined must be ascribed to water, it follows that the salt is 

 composed of 



Protoxide 38* 50 



Acid 20-«J 



Water - ^' i6 



100-00 



Remark.— This analysis corresponds very nearly with that of 

 Bucholz ^iven in the second volume of his Beitrage; but the 

 method which he followed can only be practised by a chemist 

 whose eyes are very much exercised. 



Action of Oxijmimatic Acid on Muriate of Manganese. 



I dissolved 300 grains of muriate of manganese in about 12 

 ounces of water, and made a current of oxymuriatic acid pass 

 through the solution for six hours without interruption. The 

 liquid be^an soon to froth, and the foam collected upon the 

 surface; ?t acquired a yellow colour, and concreted into a crys- 

 talline mass. This change of state made it difficult for the gas 

 to continue to pass. I allowed the apparatus to remain for a day 

 without touching it, and found next day {that a part ot the 

 mass had again become liquid, but that a great many long 

 needle-form crystals had shot in it. When the glass was opened 

 the smell of oxymuriatic acid gas was so strong as to be scarcely 

 supportable. I threw the whole upon the filter, in order to 

 separate the crystals from the liquid; but the liquid passed 

 through, and the crystals speedily deliquesced and followed it.* 

 It will appear from what follows that these crystals consisted of 

 oxymuriatic acid and muriate of manganese. Here we observe 

 the crystallization of the acid in combination with a metal. Nor 

 have I found the same thing to take place when oxymuriatic acid 

 is passed through an alkaline solution; and I do not believe that 

 any person has observed oxymuriatic acid to crystallize at the 

 temperature of 41°. . 



This solution is precipitated, by alkaline carbonates, brownish 

 red; by the pure alkalies, brown ; and by the alkaline prussiates, 

 yellowish brown. The precipitate soon becomes darker by ex- 

 posure to the air. The same thing happens to the above-men- 

 tioned crystals when dissolved in water. Whether in this com- 

 pound the manganese be really in the state of brown oxide, in 

 which state the precipitate appears, or whether it does not re- 

 ceive oxygen during its precipitation from the uncombined oxy- 



• The temperature <hirin K tlieexperimcntwaill\ the filtration wa» performed 

 at the temperature of 55°.— J. 



