139 



produces a red flame, with the formation of muriatic acid ; it is in- 

 soluble in water, and readily soluble in alcohol, ether, and oils ; and 

 nearly insoluble in acids. When heated with several metallic perox- 

 ides it is decomposed with the production of carbonic acid, and a 

 metallic perchloride. 



The author describes several experiments made with a view to 

 ascertain the proportions in which the carbon and chlorine exist in 

 this compound, from which it appears, that as one volume of olefiant 

 gas requires five volumes of chlorine for its conversion into muriatic 

 acid and this new chloride, and as four volumes of muriatic acid are 

 formed, so three volumes of chlorine must unite to two of carbon to 

 form the solid chloride. 



When this perchloride is passed through a red hot tube chlorine 

 is evolved, and a liquid compound of carbon and chlorine is obtained, 

 which assumes the form of a vapour at 170, and which, like the 

 former, is insoluble in water, but soluble in alcohol and ether, and 

 burns with the same phenomena as the solid chloride. 



The results of the author's analytical experiments upon this fluid 

 compound, induce him to regard it as consisting of one proportion of 

 each of its elements. 



By exposing the vapour of iodine and olefiant gas to the sun's 

 rays, Mr. Faraday obtained a colourless crystalline compound, diffi- 

 cultly combustible, but decomposable at a high temperature, of a 

 sweet taste and aromatic odour, and composed of iodine, carbon, and 

 hydrogen. He has not yet succeeded in forming a binary com- 

 pound of carbon and iodine, though his experiments leave little 

 doubt of the existence of such a compound, and of the possibility of 

 forming it when aided by a bright sunshine. 



An Account of the Comparison of various British Standards of Linear 

 Measure. By Captain Henry Kater, F.R.S. SfC. Read January 

 18, 1821. '[PAtf. Trans. 1821, p. 75.] 



The Commissioners of Weights and Measures having recom- 

 mended, for the legal determination of the standard yard, that em- 

 ployed by General Roy in the measurement of a base on Hounslow 

 Heath, as a foundation for the trigonometrical operations that have 

 been carried on by the Ordnance throughout the country, it became 

 necessary to examine the standard to which the report alludes, with 

 the intention of subsequently deriving from it a scale of feet and 

 inches. 



This standard consists of an iron bar, 20 feet long, described by 

 Captain Kater, in which gold points are inserted, at the distance of 

 40 inches from each other, from a standard scale of Mr. Ramsden's, 

 which was declared similar to that of General Roy, and also to that 

 of the Royal Society ; but on examining these scales, Captain Kater 

 ascertained the existence of material differences between them ; and 

 being aware of the existence of other standards of high authority, he 

 procured and compared them. 



