^06 Miscellaneous Intelligence. 



allows of the time necessary for the formation of the new 

 compounds. 



M. Becquerel mentions the natural sulphurets of zinc, iron, 

 manganese, tin, arsenic, molybdena, antimony, bismuth, copper, 

 lead, silver, and cobalt, as compounds perfectly crystallized, 

 whilst the corresponding artificial substances can be obtained only 

 in the amorphous state*. The sulphurets have no action on dry 

 oxygen gas ; but those containing very oxidable metals act on the 

 moist gas, and become sulphates or sulphites. When a metal 

 can decompose water at common temperatures, so can its sul- 

 phuret. Metals acted upon, when free, by nitric acid, are also 

 acted upon when existing in sulphurets, with the exception of very 

 few cases. Such are the general properties principally connected 

 with the present question. 



By putting into the tube a a saturated solution of nitrate of 

 silver, into the tube b a solution of hydrosulphuret of potassa, and 

 connecting the two solutions by a plate of silver, there is formed 

 after some time a deposit of metallic silver on the end of the plate 

 in o, and a double sulphuret of silver and potassium on the end in b. 

 The latter is in fine prismatic crystals, which are gradually de- 

 composed by the nitric acid, attracted in a later stage of the 

 electro-chemical action, and there ultimately remains a sulphuret 

 of silver. During the action a part of the liquid evaporates, and 

 there remains at last above the clay a pasty substance, in which 

 lies the sulphuret of silver in fine octoedral crystals, not only upon 

 the silver plate, but also on the sides of the tube. 



These crystals have the same appearance, malleability, colour, 

 and other properties of native sulphuret of silver in crystals, and 

 cannot be distinguished from them. The crystaUization is the 

 result of the slow decomposition of the double sulphuret, the 

 particles having time allowed them for that degree of motion 

 necessary to bring their homologous faces parallel to each 

 other. 



By a similar process, crystallized sulphuret of copper was 

 formed, having a grey metallic lustre, with a shade of blue, and 

 yielding a black powder. They dissolved in ammonia, rendering 

 it blue. They had, in all respects, the properties of the native sul- 

 phuret of copper. 



Leaving all things in the last experiment unchanged, except 

 that, instead of a single copper connecting plate, it was conjoined 

 with a piece of antimony, so that the antimony end should be in 

 the sulphuret, there was formed in the course of time little red 

 octoedral and lamellar crystals. These were soluble in neutral 

 hydro-sulphuret of potassa, and gave sulphuretted hydrogen 

 when acted upon by muriatic acid. Alkalis rendered them yellow. 



* There is evidently some mistake here. Bright yellow sulphuret of iron has 

 been obtained artificially from sokitions by time. Probably, many of the others 

 might be crystallized artificially j and as to antimony, it would be a difficult thing 

 to prevent crystallization. — Ed, ,, 



