830 FORMYL. 



Formiate of potash is very soluble and crystallizes with dif- 

 ficulty. Formiate of soda crystallizes in prisms of a rhombic 

 base or in tables, containing 2 atoms of water ; it is very soluble 

 and deliquescent in damp air. This salt is very suitable for 

 reducing many metallic oxides, when heated with them to 

 redness in the dry way, or when boiled with their solutions. 

 Its solution may be employed to separate the reducible metals 

 from iron, copper, manganese, &c., which are not deoxidised by 

 formic acid. 



Formiate of barytes crystallizes in brilliant transparent prisms, 

 which are persistent in air, soluble in 4 parts of water and 

 insoluble in alcohol. Formiate of strontian crystallizes in trans- 

 parent six-sided prisms, containing 4 atoms of water. Formiate 

 of lime is soluble in 10 parts of water, and scarcely more soluble 

 with heat than in the cold, so that the best mode of crystal- 

 lizing it, consists in evaporating its solution by a gentle heat. 

 A concentrated solution of the salt deposits, by evaporation, 

 needles of a brilliant lustre, which effloresce when heated. 

 Formiate of magnesia crystallizes in thin brilliant needles, per- 

 sistent in air, which are soluble in 13 parts of water and in- 

 soluble in alcohol. Formiate of alumina gives by evaporation 

 a gummy mass which is not crystalline. Its solution with 

 the addition of sulphate of potash, alum, &c., becomes turbid 

 when heated, like acetate of alumina. Formiates of manganese, 

 protoxide of iron, zinc, cadmium, nickel, cobalt, and copper are 

 very soluble and crystallizable salts. 



Formiate of cerium is a white granular and crystalline powder; 

 it is the most insoluble formiate, a property of which advantage 

 is taken in preparing pure oxide of cerium from solutions con- 

 taining oxide of iron, lime and other oxides. At 392 (200 

 centig.), this formiate enters into a kind of ebullition and is 

 converted into carbonate of cerium, without charring. 



Formiate of lead requires 36 or 40 parts of water for solution, 

 and precipitates when formic acid is added to a saturated 

 solution of acetate of lead, in brilliant needles diverging from a 

 common centre. The solution of formiate of lead has a sweet 

 taste, it is capable of dissolving oxide of lead when boiled upon 

 that oxide and acquires an alkaline reaction. Formiate of lead 

 is insoluble in alcohol. 



