Intelligence and Miscellaneous Articles. 249 



Potash precipitates a perfectly black heavy powder from the red so- 

 lution of the protosalt, which is rendered colourless at the same time. 

 This black powder is obtained also by the direct decomposition of the 

 dry salt by means of a solution of potash ; this precipitate remains 

 black after drying ; by pressure it becomes of a deep metallic lustre, 

 and by heat is reduced to metallic silver, evolving oxygen. The 

 black colour seems to indicate that it is pure protoxide of silver ; 

 but this supposition does not always depend on the colour, for this 

 powder might also be, consistently with Its properties, an intimate 

 mixture of deutoxide of silver and metallic silver, to which the prot- 

 oxide may have given rise at the moment of its separation. It is 

 also decomposed by the acids into metal and deutosalts, and am- 

 monia exerts a similar action. Hydrochloric acid converts it into a 

 brown substance,which is a chloride corresponding with the protoxide 

 or perhaps merely a mixture of silver and common chloride of silver ; 

 this substance is also obtained in the state of a brown, curdy preci- 

 pitate, which speedily subsides, by precipitating the red solution of 

 protonitrate of silver by hydrochloric acid ; it acquires the metallic 

 lustre by pressure. When heated to the temperature at which 

 chloride of silver fuses, it becomes merely a yellow mass, and is a 

 mixture of silver with the common chloride. When treated with 

 ammonia, or even with concentrated solution of the hydrochlorate, 

 the brown chloride is decomposed immediately into chloride which 

 is dissolved, and into metallic silver which remains. 



Oxalate of silver when exposed at 212° to the action of hydrogen 

 gas, becomes of a bright yellow tint ; but the decomposition seems 

 to remain only partial at this temperature. It became brown at 

 284° ; but it soon afterwards produced a very loud explosion. 

 Succinate of silver becomes lemon-yellow at 212° in hydrogen gas. 

 At a higher temperature, half of the succinic acid sublimed. The 

 protosuccinate of silver thus formed is insoluble in water. Pure 

 deutoxide of silver is reduced to the metallic state precisely at 212*^ 

 in hydrogen gas. — Journal de Pharm. Juillet 1839. 



ON CUBEBIN. BY MM. CAPETAINE AND SOUBEIRAN. 



We have discovered on cubebs a peculiar matter, to which we 

 give the name of Cubebin. Although M. Monheim has already ap- 

 plied this word to a product which he obtained in his experiments 

 on cubebs, it is certain that he did not procure the true cubebin, as 

 may be seen by the properties which he assigns to it. The cubebin 

 of M. Monheim is greenish, has an acrid taste, melts at 68°, boils 

 at 86°, and then is partly volatilized, whereas the true cubebin is 

 white, insipid, inodorous, and decomposes before it fuses. 



The process which we found to succeed best in obtaining cubebin, 

 consists in pressing the marc which remains after the preparation 

 of the volatile oil of cubebs to make an alcoholic extract of it, and 

 to treat this extract with a solution of potash, as proposed by 

 Poulet for the preparation of pipesin. The cubebin is to be washed 

 with a little water, and to be purified by crystallization repeatedly 

 from alcohol. 



