Intelligence and Miscellaneous Articles. 525 



iodide dissolved. The use of nitrate of lead appears to have been 

 preferred by several chemists ; and M. Baudrimont expressly recom- 

 mends it, on the ground that the acetate yields some oxiodide. 



This first point being established, it remained to explain the loss 

 of the 10 per cent, occurring by the use of acetate of lead; and 

 presuming that the acetate of potash, formed with the iodide of lead, 

 took some part in this phsenoraenon, the action of this salt on iodide 

 of lead was examined, and the results were as follows : — 



When iodide of lead is triturated with acetate of potash, the mix- 

 ture becomes rapidly moist, gradually loses its colour, and soon be- 

 comes perfectly white. This pasty mixture does not act upon litmus 

 paper and pulverized acetate of lead. When exposed to the air it 

 partially liquefies, and partially crystallizes in silky needles of double 

 iodide of potassium and lead : on contact with water it becomes im- 

 mediately yellow, reviving yellow iodide, and the liquor becomes 

 acid ; and when filtered it yields a pale yellow precipitate with tris- 

 acetate of lead, and regenerates bright yellow iodide, when nitric 

 acid, or dilute sulphuric acid is added. By evaporation it leaves a 

 white deliquescent residue, which regenerates yellow iodide on con- 

 tact with water. If, instead of water, alcohol be added to the pasty 

 mixture of acetate of potash and iodide of lead, it partly dissolves ; 

 the residue, which is almost white, yields yellow iodide on contact 

 with a weak acid ; and the supernatant liquor does the same on the 

 addition of nitric acid. 



When, on the other hand, iodide of lead is treated with a hot so- 

 lution of acetate of lead, a colourless acid liquor is obtained, which 

 yields white silky crj-stals of double iodide of potassium and lead, 

 and a yellowish-white insoluble residue of oxiodide of lead. — Journ. 

 dePh.et de Ch., Avril 1847. 



[Note. — A parallel case occurs when acetate of lead is decomposed by 

 chloride of sodium, as will appear by the following remarks in the last edi- 

 tion of my translation of the Pharmacopoeia, p. 280. " I have lately found, 

 however, that the decomposition is not complete. A double salt is formed, 

 the nature of which I have not yet examined, but which is to a considerable 

 extent soluble in water. Hydrochloric acid occasions the precipitation of 

 more chloride of lead after the action of the chloride of sodium is over." — 

 R.P.] 



ON THE ACTION OF BROMI.NE UPON CERTAIN SALTS. 

 BY M. AUGUSTE CAHOURS. 

 Alkaline oxalates. — When bromine is gradually dropped into a 

 solution of oxalate of potash or soda, containing a slight excess of 

 alkali, no action ensues if the temperature be low ; but if it be raised 

 to 104^ or 122° F., action immediately commences, and l)ecomes very 

 vivid ; nmch gas is disengaged, which extinguishes flame, yields 

 a white precipitate with lime-water, and is totally absorbed by 

 a solution of jjotash ; thus possessing all tlie pro])erties of pure car- 

 bonic acid. The li(juor contains the bromide of potassium or sodium, 

 which may be obtained in fine crystals by spontaneous evaporation. 

 The oxalates of barytcs, lead and silver, arc similarly acted upon. 



