APPENDIX. 663 



containing azote, and states several other objections to which it 

 is unnecessary to refer. * 



In 1831, Liebigf made known an apparatus which he had con- 

 trived, and which greatly facilitated the determination of the 

 weight of carbonic acid gas formed during the analysis of orga- 

 nic bodies. The water formed was determined, as Berzelius had 

 done, by causing the products of the combustion to pass through 

 a tube filled with fragments of chloride of calcium. The increase 

 of weight gave the water evolved. The contrivance for collect- 

 ing the carbonic acid was a glass tube upon which were blown 



the two large bulbs , a, and the three small intermediate bulbs 

 b f b 9 b 9 the capacity of all the three being only equal to^that of 

 one bulb a. The bulbs b t b, b, are filled to the line c, with a 

 saturated solution of caustic potash, and the whole tube with its 

 contents, after being accurately weighed, is luted by the extremity 

 d to the tube containing the chloride of calcium. The glass 

 tube containing the mixture of oxide of copper and the substance 

 to be analyzed, after being repeatedly exhausted by means of a 

 syringe attached to it, passing through a tube filled with chlo- 

 ride of, calcium to get rid of moisture, is luted to the other ex- 

 tremity of the tube containing the chloride of calcium, and placed 

 horizontally on a small iron grate, and heated gradually and 

 slowly by means of ignited charcoal, and this is continued till 

 the process is finished, which, if properly conducted, will occupy 

 about two hours. The increase of weight in the chloride of cal- 



* Poggendorf's Annalen, xviii. p. 357. f Ibid. xxi. 1. 



