398 Intelligence and Miscellaneous Articles. 



oxygen to sulphurous acid ; but the peracetate of iron becomes pro- 

 toacetate by its action. 



9th. Molybdic acid is not reduced by sulphurous acid, but mo- 

 lybdate of potash is reduced to a low state of oxidizement, to the 

 blue compound or molybdous acid. — Journal de Pharmacie et de 

 Chimie, Sept. 1843. 



EXTRACTION OF PALLADIUM IN BRAZIL. 



The extraction of palladium from the auriferous sand of Brazil 

 consists in fusing it with silver, and consequently forming a quater- 

 nary alloy of gold, palladium, silver and copper, which is granulated 

 by projecting it into water. 



By treating this alloy with nitric acid the gold is separated from 

 the other metals which are soluble in the acid ; the silver is precipi- 

 tated by a solution of common salt in the state of insoluble chloride, 

 which being separated, the copper and palladium are precipitated by 

 plates of zinc. The pulverulent deposit of these metals is redissolved 

 in nitric acid and the solution precipitated by excess of ammonia, 

 which redissolves the oxide of copper and of palladium ; when the 

 ammoniacal solution of these metals is saturated with hydrochloric 

 acid, a double chloride of palladium and ammonia is deposited in the 

 state of a crystalline yellow powder, and this when calcined in a 

 crucible is readily decomposed, and leaves spongy palladium — 

 Journal de Chemie Medical, October 1843.* 



ON THE INFLUENCE OF TEMPERATURE ON THE PRODUCTION 

 OF IODOFORM. BY M. BOUCHARDAT. 



Many instances of the influence of temperature in chemical reac- 

 tions are known, to which M. Bouchardat has added that which it 

 exerts in the production of iodoform. 



If to water containing iodide of potassium and a little alcohol, 

 iodine and potassium be alternately added in sufficient quantity to 

 decolorize and colour the liquor, it becomes hot, and there are 

 successively produced acetic aether, and iodoform without any trace 

 of iodate of potash. 



But if instead of this the iodine be dissolved in the water and al- 

 cohol holding iodide of potassium in solution, and to these there be 

 added an aqueous solution of potash, but not in sufficient quantity 

 to decolorize the liquors, and then fresh iodine be added and suc- 

 cessively potash in sufficient quantity to decolorize, then no trace 

 of iodoform is produced. The oxygen which the iodine displaces 

 from the potash acts upon the alcohol to convert it into acetic aether, 

 which may be easily separated ; but the action goes no further ; as 

 soon as the alcohol is converted into acetic aether, the oxygen dis- 

 placed acts upon the iodine to produce iodate of potash which is 

 deposited. 



Thus with excess of iodine at common temperatures, there is no 

 * See p. 16 of the present volume. 



