Intelligence and Miscellaneous Articles. 157 



probably discover some source of error in his processes, or it may 

 turn out that the mineral is only a variable mixture of the elements 

 of which it is composed, and not a definite species. — R. P. 



ON THE REDUCTION OF POTASSIO-CHLORIDE OF PLATJNA. 



M. Parisot observes that chloride of platina is employed in labora- 

 tories to ascertain the presence of potash and its salts in solution ; 

 and being- consulted as to a method of easily separating the platina 

 of the double chloride, he found that it might be effected by means 

 of zinc. 



The process consists in taking the precipitate of chloride of pla- 

 tina and potash, or the liquid which holds it in solution, and com- 

 pletely dissolving it in water, and the solution is then to have sul- 

 phuric added to it. Into this acid liquid a cylinder of zinc is to be 

 immersed ; decomposition of water occurs, attended with the evolu- 

 tion of hydrogen and the formation of sulphate of zinc ; this re- 

 mains in solution, while the platina is precipitated in the state of a 

 black powder. 



The reaction is maintained, with the disengagement of hydrogen, 

 by adding a little sulphuric acid, until all the platina is precipitated, 

 which is known to be the case when the liquor is perfectly colourless. 



When the platina is reduced it is collected on a filter, washed 

 with boiling water, then dried, and afterwards treated with a little hot 

 hydrochloric acid, to deprive it of any zinc which it may retain, and 

 lastly it is to be washed with boiling distilled water. — Journ. de 

 Chim. Med. Avril, 1840. 



DR. BARRY ON THE CORPUSCLES OF THE BLOOD. 



We are requested by Dr. Martin Barry to mention, that the rapid 

 and incessant changes in the form of the blood-corpuscles observed 

 by him in certain altered states, described in a paper read before 

 the Royal Society, June 4, 1840, are caused, as he has subsequent 

 reason to believe, by contiguous cilia. 



ACECHLOR-PLATINA. 



M. Zeise obtains this compound by triturating chloride of platina 

 with a sufficient quantity of acetone to form a thin paste, and leaving 

 the mixture in close vessels from 38 to 40 hours. During the so- 

 lution of the chloride heat is given out, and an irritating vapour, 

 mixed with hydrochloric acid, is evolved. A fluid, brownish, black 

 compound, is at first formed, but the greater part becomes a crystal- 

 line mass in about 24 hours ; when the fluid portion has been se- 

 parated, the mass becomes of a yellow colour when treated with 

 small portions of acetone on a filter. The mother liquor contains 

 some acechlor-platina, which may be obtained by distilling it to dry- 

 ness with the acetone which has been used in washing ; the blackish 

 mass obtained is to be treated on a filter with fresh portions of 

 acetone. 



