Chemical Science. 429 



passed through it, abundance of kermes falls down ; and on the 

 addition ol diluted sulphuric acid to the solution so treated, a 

 second portion of the golden sulphuret is obtained : both these 

 preparations have a fine and beautiful appearance. 



9. Jodo-cyanuret of Potassium and Mercury. When solutions 

 of prussiate of mercury, and hydriodate of potash, are mixed, 

 abundance of crystals fall down, which, when collected, washed, 

 and re-crystallized, appear in large thin brilliant plates unalterable 

 in the air, without smell, but in solution having the odour of 

 bitter almonds ; soluble in 16 times their weight of cold water, 

 and in much less when hot; soluble in 96 parts of alcohol. Their 

 composition has not been determined, but 24 parts gave, with 

 hydro-sulphuret of soda, 13 parts of sulphuret of mercury. — 

 Caillot. An. de Chim. xix. p. 280. (See our Foreign Science.) 



10. Hydriodide of Carbon. In the Philosophical Transactions, 

 for 1821, I have described a compound of chlorine and defiant 

 gas, but had not at that time the means of ascertaining its com- 

 position. Since then, 1 have obtained it in greater quantity, 

 and analyzed it. Four grains were passed in vapour over heated 

 copper, in a green glass tube; iodide of copper was formed, 

 and pure olefiant gas evolved, which amounted to 1.37 cubic 

 inches. As 100 c.i. of olefiant gas weigh about 30.15 grs., so 

 1.37 c.i. will weigh 0.413 of gr. Now 4 grains minus 0.413 

 leaves 3.587 iodine, and 3.587 : 0.413 : : 117-75 : 13.55 nearly. 

 Now 13.55 is so nearly the number of 2 proportions of olefiant 

 gas, that the substance may be considered as composed of 



1 proportion of iodine .... 11 7-75 



2 proportions of olefiant gas . . 13. 4 



and is therefore analogous in its constitution to the compound of 

 chlorine and olefiant gas, sometimes called chloric ether. M. F. 



1 1 . Formic Acid, and Formate of Lead. The following estima- 

 tions of the composition of these bodies is given by Dr. Gobel 

 from careful experiments : 



Formate of lead 1 atom oxide of lead . • 107.5 



1 formic acid . . 34.9 



I water 8.45 



Formic acid 



Carbon . . . 11.35, or 2 atoms oxide carbon . . 26.4 



Hydrogen . . 1.06, 1 water 8.45 



Oxygen . . . 22.43 

 .34.84 

 Vor.. XIII. 2 G 



34.85 

 Jnnals Phil. iii. 46S. 



