'Intelligence and Miscellaneous Articles. 393 



this acid is present however, the hydrochloric acid becomes rapidly 

 brow^n, by repose depositing a precipitate of that colour, consisting 

 of an intermediate sulphuret of tin, of proto-sulphuret and of chloride 

 of tin insoluble in muriatic acid. This reaction depends upon a por- 

 tion of the tin becoming oxidated at the expense of the sulphurous 

 acid, another portion uniting with the sulphur, while the oxide of 

 tin thus formed dissolves in the excess of muriatic acid to form an 

 insoluble chloride. — Journ.fiir Pract. Chemie, 6. 81. 



PROCESSES FOR PREPARING LITHIA. BY FUCHS. 



1. Lepidolite is to be ignited during two hours with li or 2 parts 

 of quicklime, and the mass left during two or three monthf5 exposed 

 to the air, it being kept constantly moist with water. The whole is 

 then to be powdered and treated with water, which dissolves out po- 

 tassa and lithia ; the solution is then saturated by a current of car- 

 bonic acid gas and evaporated to dryness. Tlie residue, which con- 

 sists of the carbonates of potassa and lithia, is digested with water 

 containing a little alcohol, which dissolves the carbonate of potassa 

 and leaves the carbonate of lithia. 



2. Seven parts of lepidolite are ignited with 2 of calcined vitriol, 

 taking care that the mixture never melts. The mass when cold is 

 powdered and boiled with water, which dissolves out the sulphates 

 of lithia and potassa : the solution is then evaporated to dryness, and 

 the salt of lithia dissolved out by water, to which a little alcohol has 

 been previously added, — Jahres-Bericht der Phys. Wissenschaften 

 •16. 97. 



NEW DOUBLE SALT OF ZINC AND POTASSIUM. BY ANTHON. 



When a solution of iodide of potassium is mixed with one of ni- 

 trate of zinc, a yellowish crystalline deposit of iodide of zinc falls, 

 which dissolves on the addition of an excess of iodide of potassium, 

 and by evaporation crystallizes in colourless octohedral or rhombic 

 crystals, which are not altered by exposure to the air, and contain 

 iodine, nitric acid, zinc, and potassa. By exposure to heat this salt 

 evolves iodine, then nitrous acid, oxide of zinc and potassa being left ; 

 it is readily soluble in water, insoluble in alcohol ; acids precipitate 

 iodine from its solutions, tartaric acid separating bitartrate of potassa. 

 — Buchner' s Repertorium, 1. 115. 



REAGENT FOR NITRIC ACID AND NITROGEN. BY DESBASSAYNS 

 DE RICHEMONT. 

 Th^ mode of detecting the presence of nitric acid proposed by De 

 Richemont is exceedingly delicate, and depends upon the fact, that 

 a mixture of a concentrated solution of protosulphate of iron and sul- 

 phuric acid becomes coloured rose-red by the addition of deutoxide 

 of nitrogen {Stickoxyd), or even purple if the latter is present in 

 larger proportion : the quantity of the nitric oxide necessary for the 

 production of this tint is so small that an exceedingly minute portion 

 may be detected by it. To detect the presence of nitric acid, add 

 to a small quantity of sulphuric acid the solution to be examined, in 



