524' Intelligence and MisccUaiieoiis Articles. 



soluble in sotber and in acetone. It fuses at about 334'^ F. into a 

 deep red-coloured and very transparent liquid, and on cooling it 

 becomes a vitreous mass. After having been fused, it dissolves 

 readily in aether and in alcohol ; but these solutions, when evaporated, 

 yield merely amorphous masses. At about 544° F. it carbonizes, 

 3'ielding a small quantity of an oily body, and very little gas. When 

 heated in the air, it burns with flame, and leaves no trace of residue. 



Dry chlorine does not act upon dry carotin ; but water saturated 

 with chlorine converts it into a perfectly colourless chlorinated body, 

 which is insoluble in water, but is considerably soluble in alcohol and 

 a?ther, and very much so in sulphuret of carbon. The solutions, 

 when evaporated, yield merely a friable resinous mass. 



By elementary analysis, carotin appears to be a compound of car- 

 bon and hydrogen in the atomic relation : 10(C* H"^). It is therefore 

 a polymeric of oil of turpentine, a circumstance which is of unques- 

 tionable interest. — Ann. de Ch. et de Phys., Mai 1847. 



ON THE PREPARATION OF IODIDE OF LEAD. 



M. Boudet observes that M. Depaire, pharmacien of Brussels, has 

 stated that when iodide of lead is prepared bj'^ the reaction of ace- 

 tate of lead and iodide of potassium, the supernatant liquor contains 

 a considerable quantity of iodine. He found that this liquor, in which 

 acetate of lead produced no turbidness, gave a yellow precipitate of 

 iodide of lead on the addition of a little nitric acid, a precipitate of 

 trisiodide of lead with trisacetate, and free iodine with sulphuric and 

 hydrochloric acids ; and submitted to evaporation, leaves a white 

 residue, which on the addition of water, regenerates iodide of lead. 



From these facts M. Depaire concluded, that in employing acetate 

 of lead to extract iodine from iodine baths, loss of iodine was sus- 

 tained ; to avoid which, he proposes, as M. Cottereau, jun. had 

 previously done, to employ the trisacetate of lead, which j)recipitates 

 the iodine perfectly. 



M. Depaire afterwards examined in what state the iodine could be 

 retained in the solution from which the iodide of lead was precipi- 

 tated ; and after having ascertained that it was not in a state of 

 simple solution, he appeared disposed to think that it exists in the 

 state of potassio -iodide of lead. 



M. Boudet states that experiments, which he performed four years 

 ago, but which he neglected to publish, confirm the remarks of M. 

 Depaire ; and he is enabled to add some observations, which, he 

 thinks, will not be uninteresting. 



Having ascertained that in preparing iodide of lead with acetate 

 and excess of acid, the weight of the product obtained was less 

 than indicated by theory, to the amount of about 10 per cent., 

 M. Boudet added some nitric acid to the solutions which ceased to 

 precipitate with acetate, and he obtained an additional yellow preci- 

 pitate of iodide of lead. This suggested the employment of nitrate 

 instead of acetate of lead in preparing the iodide ; and on trial it was 

 found to yield such a product as theory would indicate, minus the 



