1 52 Intelligence and Miscellaneous Articles. 



by decomposing a solution of the magnesian salt with solution of 

 ammonia, as long as precipitation takes place ; tlien filter and eva- 

 porate. Lactate of lead is also a gummy salt ; but having loft a 

 syrupy solution for a long time, a granular salt was obtained, which 

 by drying became light and as brilliant as silver, it does not alter 

 by exposure to the air, and dissolves in alcohol. In general lactic 

 acid has the property of yielding a salt of lead, which is soluble in 

 alcohol, a character by which it is distinguished from many other 

 acids. When the neutral salt is decomposed by a small quantity of 

 ammonia, a subsalt is precipitated ; it is also obtained by digesting 

 the neutral salt with an excess of oxide of lead, which swells up. 

 The subsalt dissolves with difficulty in water; it is most frequently 

 coloured with extractive matter ; its aqueous solution is rendered 

 turbid by the carbonic acid of the air, has an alkaline reaction, 

 and an astringent taste. When it is boiled in water, and the boiling 

 solution is filtered, the greater part of the salt is precipitated in the 

 state of a light yellow powder. If this subsalt be dried, it becomes 

 farinaceous and soft to the touch ; and if it be ignited, it burns like 

 amadou, and leaves metallic lead amounting to about -rVo of the salt 

 employed. 



Lactate of copper is green, and does not crystallize. According 

 to Scheeie the lactate of zinc crystallizes. The perlactate of iron is 

 of a red brown colour, gummy and insoluble in alcohol. The proto- 

 lactate of mercur)' is deliquescent, and dissolves in alcohol; but it 

 is easily decomposed by it, yielding carbonate of mercury, and the 

 liquid acquires an asthereal odour. The perlactate of niercury is 

 red, gunnny, and deliquescent. After some weeks it deposits a semi- 

 crystalline j)owder, which has not yet been examined. Lactate of 

 silver is a soft transparent gummy mass, which has a disagreeable 

 taste, is soluble in alcohol, and is slightly decomposed by it; it be- 

 conics greenish-yellow by drying, and red when redissoived in water; 

 it then depo.sits a brown precipitate. 



What has now been stated refers to lactates more or less mixed 

 with alcoholic extract; they are yet unknown in a state of purity. 

 'J"hose who may occupy themselves with this subject in future, ought 

 principally to direct their attention to determining whether what is 

 called lactic acid is a mixture of two acids, which resemble each 

 other, but which give different salts. — Ann. de Chim. et de Ph. xlvi. 

 420. 



ACETATE OF LEAD AND PYROACETIC SPIRIT. BY M. MATTEUCI. 



Acetate of lead, when exposed to a gentle heat, begins to fuse at 

 136° Fahr. ; the liquid mass boils at 212°, and afterwards condenses 

 into a very white mass at nearly the same heat. During this first 

 fusion of the acetate of lead, it loses merely the three atoms of water 

 which it contained. When heated above the temperature at which 

 it becomes solid, it undergoes a second fusion, and at 536° it is com- 

 pletely liquid. It boils for some time, and after having acquired a 

 brownish colour, it again becomes solid, and has a dirty white co- 

 lour, without any appearance of crystallization ; this mass is trisa- 



cetate 



