164 INORGANIC AGENTS 



Magnesii Caebonas. Magnesium Carbonate. 

 (MgCo,),. Mg(OH), + 5 H,0. (U.S. P.) 



Synonym.— M-SLgnesii carbonas ponderosa, or magnesii 

 carbonas levis, B. P.; magnesia alba, magnesia hydrico- 

 carbonica, carbonas magnesicus, carbonate of magnesia, E.; 

 magnesia carbonica, P. G.; carbonate de magnesie, magnesie 

 blanche, Fr.; weisse magnesia, G. 



Derivation.— Mix conceutrated, boiling, aqueous solu- 

 tions of magnesium sulphate and sodium carbonate, and 

 evaporate. 



5 MgSO, + 5 Na, CO3 + H,0 = (MgCOJ, Mg^OH), 

 + 5 NAjSO, + CO,. Purified by digestion with water, 

 filtration and drying. 



Properties.— Slight, white, friable masses (heavy mag- 

 nesium), or a light, white powder (light magnesium), wither. fc 

 odor, and having a slightly earthy taste ; permanent in the 

 air ; almost insoluble in water, to which, however, it imparts 

 a slightly alkaline reaction ; insoluble in alcohol. 



Z)ose.— Foals and calves, 3 i--ii- (4.-8.); D., gr.v.-3i. 

 (.3-4). 



Magnesh Oxidum. Magnesium Oxide or Magnesia. MgO. 



(U. S. P.) 



Synonym. — Magnesia levis, light magnesia, B.P.; calcined 

 magnesia, magnesia calcinata, E.; magnesia usta, P. G.; 

 magnesie, magnesie calcinee, Fr.; gebrannte magnesia, G. 

 ' Derivation. — Heat magnesium carbonate. 4 (MgCO,). 



Mg(OH), -t- 5 H,0 = 5 MgO + 6 H,0 -t- 4 CO,. Water 

 and carbon dioxide are driven off and magnesia (MgO) is left. 



Properties. — A white, very light, very fine powder, with- 

 out odor, and having an earthy, but not a saline taste. On 

 exposure to the air it absorbs moisture and carbon dioxide ; 

 almost insoluble in water ; insoluble in alcohol. 



Dose. — Foals and calves, 3 i.-ii. (4-8.); D., gr.v.-3L 

 (.3-4). 



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