1814.] Chemical Knowledge of Manganese. 415 



solution liydrogen gas is evolved, which has the smell of asafoetida. 

 The solution has at tirst a greenish colour, owing to the quantity of 

 green oxide formed. Wlien it is nearly saturated it becomes pale 

 red. A siiiail quantity of charcoal, previously contained in the 

 metal, remains behind undissolved, as happens in all solutions of 

 this metal. 



I. Qn the green Oxide. 



This acid dissolves the green oxide quietly, and the carbonate 

 with strong eifervcscence. The solution has a faint red colour^ and 

 crystallizes very readily. 



Properlies of the aystaUized Salt. 



The crystals have the following shapes : 1 . A somewhat oblique, 

 four-sided prism. 2. A double four-sided pyramid, having the 

 alternate edges of the common basis truncated. 3. An equal four- 

 sided table, with flat ends, and two of the sides narrower than the 

 other two. These two narrow sides and the edges of the table are 

 often truncated. 



The crystals are usually transparent. Taken separately they ap- 

 pear colourless; but when viewed in considerable groups, they have 

 a weak red colour, and a very strong lustre. Their ta'^te is acid 

 and salt. They are not altered by exposure to the air. When 

 heated they become opake and white, and assume the appearance of 

 porcelain. 



At the temperature of 66°, they dissolve in ten times their weigiit 

 of water. They are insoluble in alcohol. 



100 grains of this salt were distilled in a small pneumatic appa- 

 ratus. There came over, first, water, ti.en a yellowish grey 

 smoke, and lastly a brown oil. During this ti.ne a considerable 

 quantity of gas was disengaged, which was at first pure carbonic 

 acid, and afterwards a mixture of carbonic acid and carljureted 

 hydrogen. The residue freed from the remains of the succinic 

 acid, consisted of 30-27 of green oxide. Hence 100 parts of 

 succinate of manganese consist of 



Green oxide 30*27 



Acid and water G9*37 



100-00 



ACTION OF ACKTIC ACID. 



a. On (he Metal. 



Acetic acid acts upon manganese very slowly, but cofiipletely 

 disiolvcs it at last. The solution has a reddish colour and readily 

 crystallizes. 



h. On the green Oxide. 



Concentrated acetic acid dissolves both the green oxide and the 

 carbonate of manganese. \u order to saturate the acid completely, 

 it must be digested for some days on the oxide. 



