78 Scientific Intelligence. [July 



It was found to consist of 



Dry iodide . . . 94*95 

 Water 5*05 



10000 

 It is insoluble in water, alcohol and ether. 



It is not decomposed when heated to the boiling point in a con- 

 centrated sulphuric acid bath. A little above the boiling point of 

 mercury ((J68°), it parts with a portion of its iodine. It con- 

 sists of 



Iodine 70 60 



Palladium . . . 29-40 



100-00 



Hence it is obviously a simple iodide. 



When hydriodic acid is poured upon the iodide of palladium no 

 action takes place, which affords a distinction between the iodide of 

 platinum and palladium, for the former produces a soluble combina- 

 tion with this acid. 



The iodide of palladium, newly precipitated, when mixed with a 

 solution of iodide of potassium, forms a dark wine-coloured solution, 

 which contains a double iodide, and is not altered by the air or heat. 

 When evaporated, grayish black cubical crystals are obtained, which 

 are a double iodide of palladium and potassium. 



The hydrous iodide of palladium combines with ammonia when 

 digested in caustic ammonia. By evaporation, orange crystals of 

 ammonia and iodide of palladium are procured. 



Caustic potash precipitates the oxide of palladium when boiled 

 with iodide of palladium. Bi-iodide of iridium is prepared by 

 mixing a solution of iodide of potassium with a solution of the 

 bi-chloride of iridium, adding an excess of muriatic acid, and bring- 

 ing the liquid to a boiling temperature. A black powder precipi- 

 tates, which is the bi-iodide of iridium. It is insoluble in water 

 and acids. It decomposes at nearly the same temperature as the 

 bi-iodide of platinum, leaving metallic iridium. — {Lassaigne, 

 Journ, de Chim. Medic, i. 57.) 



XI . — Volvox glohator (of Muller). 



This is a little insect which is constantly revolving, and contains 

 other globules endued with motion which are independent of the 

 animal. It lives in still waters among confervae, and is of a beauti- 

 ful gray colour. Braconnot {Ann. de Chim. Ivii. 440.) collected a 

 number of these insects in the month of November. They formed a 

 gelatinous green mass. Hot alcohol became of an emerald green colour; 

 the animals became white. The residue and the solution when 

 evaporated formed a soft deep green fatty matter, which was reddened 

 by nitric acid, and was not dissolved in potash. It was identical with 

 vegetable chlorophylle. This matter gave up to water a little chlo- 

 ride of potassium. The matter which was not dissolved by the 

 alcohol was treated with boiling water. A little mucilaginous 

 matter was taken up. 



