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II. 'Notices in Analytical Chemistry. By Mr. T. Richardson*- 



1. Notice of an Analysis of the Sesquichloride of Carbon. 



'X'HIS substance was formed in the usual way by passing 

 -■■ a current of pure chlorine gas through the liquid of the 

 Dutch chemists, till a sufficient quantity was obtained for ana- 

 lysis. The crystalline substance obtained was at first well 

 washed with distilled water, and after repeated crystallization 

 from different solutions in alcohol, was considered pure. In 

 this state it had scarcely any taste, an odour similar to that of 

 camphor, and possessed, in short, all the characters of pure 

 sesquichloride of carbon. 



Analysed in the usual way by means of Liebig's apparatus, 

 •772 gram, of the crystals dried at 300° Fahrenheit, gave 

 •291 grm. COg, and '006 HgO grm. water. The small 

 quantity of hydrogen evidently arises from hygrometric moist- 

 ure, and allowing the deficiency to be chlorine, we have 



Carbon 10-42 



Chlorine 89-58 



100-00 

 which is equivalent to 



1 atom carbon...... 76-4<4< 10-30 



3 atoms chlorine... 663-96 89*70 



740-40 100-00 



2. On the Employment ofChromate of Lead in the Analysis of 

 Orga7iic Substances f. 

 The chromate of lead may be prepared by mixing a salt of 

 lead with bichromate of potash, and carefully washing the 

 precipitated salt. The pure salt, when perfectly dry, is to be 

 heated in a clay crucible till it melts. When well melted it 

 does not absorb so much moisture, and possesses in this re- 

 spect a great advantage over the oxide of copper. Before 

 employing the salt in analysis it should be finely pounded, 

 and afterwards placed for a short time in a warm place to 

 expel any hygrometric moisture. The mixture with the or- 

 ganic body to be analysed, is made in precisely the same way 

 as with oxide of copper, only that it ought to be as intimate 

 as possible, since a larger portion of substance becomes ex- 

 posed to the action of the heat in the same time, than with 

 the oxide of copper. The length of the tube necessary for 

 combustion is about 10 inches long and 4ths of an inch in 



* Communicated by the Author. 



t From the Transactions of the Nat. Hist. Society of Northumberland, 

 Durham, and Newcastle-upon-Tyne, vol. ii, p. 41S. 



