CARBON AND CARBONIC ANHYDRIDE. 91 



gases, and then, by taking away the carbonic anhydride, he 

 has the carbonic oxide by itself. The way in which he 

 does this is represented in Fig. 25 (p. 90). The oxalic acid 

 and the sulphuric acid are put into the flask, a, and on the 

 application of gentle heat the two gases, carbonic anhydride 

 and carbonic oxide, are produced, and pass over through the 

 tube into the bottle, b. Here there is a solution of potassium 

 hydrate; and as the gases pass into it the carbonic anhy- 

 dride unites with the potassium to form potassium carbon- 

 ate, and the carbonic oxide goes on alone into the jar, c, where 

 it is received for experiments. 

 114. Experiment. If you 

 take a jar of this gas, Fig. 26, 

 and apply a lighted taper to 

 its mouth, the gas will burn 

 with a beautiful blue flame. 

 You can make the flame very 

 large by pouring water in, for 

 this forces the gas out rapidly. 

 As it burns it becomes carbonic 

 anhydride by taking oxygen 

 from the air. Fig. 20. 



Carbonic oxide. Oxygen. yield Carbonic anhydride. 

 CO + O = CO 2 



QUESTIONS. 



89. In what forms does carbon occur in nature ? 90. How is charcoal 

 made? How illustrated? 91. What is soot? What is said of imperfect 

 combustion ? Why do lamps smoke when the wick is too high ? 92. How 

 is lampblack made ? 93. What is bone-black ? What does it contain be- 

 sides charcoal ? What are some of its uses ? 94. What is said of the pres- 

 ence of carbon in animal substances ? What is the chemical explanation 

 of the charring of flesh and skin ? What is said of overcooking meat ? 

 (>."). What of the unchangeably of charcoal ? What of its preservative 

 power? What of its purifying and decolorizing powers? What other 



