142 HISTORICAL INTRODUCTION TO CHEMISTRY CHAP. 



" The experiments were made and the results agreed per- 

 fectly with our view. 



"To 16 grams of carbonate of baryta made directly, 5 

 grams of charcoal were added and the mixture was heated 

 in an apparatus similar to that used for the reduction of the 

 oxide of zinc. 



" After three hours' heating, a hole was formed in the 

 retort, and the heating was stopped : there had been collected 

 three litres of a gas of which the first portions contained 1/6 

 of carbonic acid and 5/6 of an inflammable gas similar in 

 every respect to carbonic oxide. The last portions contained 

 hardly any carbonic acid. 



"In the residue were found 1*64 gram of pure baryta." 

 (loc. tit., p. 45.) 



Desormes and Clement prepare carbonic oxide by re- 

 ducing carbonic anhydride with charcoal. Desormes 

 and Clement made many attempts to prepare carbonic 

 oxide by the direct combination of carbon with air or 

 oxygen. They found that carbonic anhydride was in- 

 variably formed as the first product of combustion, but 

 that this gas could be reduced to carbonic oxide by passing 

 it through red-hot iron tubes packed with charcoal (loc. tit., 

 p. 46). The gas was passed to and fro until no further 

 increase of volume was caused by the reduction. At the 

 present time large quantities of inflammable gas are manu- 

 factured in this way, by passing air through hot coal or coke ; 

 the oxygen first forms carbonic anhydride, which is then con- 

 verted into carbonic oxide by the excess of hot fuel ; the 

 product, known as PRODUCER GAS, consists mainly of 

 carbonic oxide and carbonic anhydride, diluted with large 

 volumes of nitrogen. 



Desormes and Clement decompose water by means of 

 charcoal. It was well known that large quantities of 

 inflammable gas could be produced by heating moistened 

 charcoal. The nature of this process was elucidated by 

 De'sormes and Clement, who showed that the charcoal 



