RESEARCHES UPOIST THE CHEMICAL PROPERTIES OF GASES. 191 



The change is checked at higher temperatures, hydrogen being liberated at 300°. 

 The volatile formic acid easily liberated from the sodium formate (by decomposition 

 and distillation with tartaric acid) may be recognized by its reducing action upon 

 aramoniacal silver nitrate solution. The purest caustic soda obtainable often con- 

 tains substances of a reducing nature, and it is necessary to use soda free from such 

 impurities. If the formate of soda extracted by water from the soda lime be acidu- 

 lated and distilled, the formic acid obtained in the distillate may be tested for by 

 silver solution. 



Carbon monoxide is oxidized to carbon dioxide by steam alone, at 900° (N"au- 

 mann and Pistor, Ber., 1885, p. 2724). 



Action of Carhon Monoxide upon Methane {Natural Gas) at High Temperatures. 



According to Odling {Watfs Die, Yol. I, p. 1111), the following reaction 

 occurs when methane and carbon monoxide are passed through a heated tube : 



CH, + CO ="H,0 + C2H2. 



Natural gas from Murrysville, Pa., having the following composition, was used 

 in the experiment detailed below : 



Methane 95.40 



Carbon dioxide , 0.20 



Nitrogen 4.40 



100.00 



Natural gas mixed with carbon monoxide in the proper proportion (both being 

 carefully freed from COo) was passed through a porcelain tube filled with bone-black 

 (previously purified from lime salts by muriatic acid). 



The tube was heated by a coke fire with a strong draft to a temperature which 

 finally caused softening of the porcelain tube. The escaping gases were passed 

 (1) into lime water, (2) into aramoniacal cuprous chloride. No trace of a red pre- 

 cipitate appeared in the cuprous chloride solution such as would have formed if 

 acetylene had been produced. On replacing the cuprous chloride solution by bromine 

 water, no oily drops collected in the fluid such as would have formed if an olefine had 

 been produced. I have failed, therefore, to show that methane in contact with car- 

 bon monoxide at a high temperature gives rise to the formation of an unsaturated 

 hydrocarbon. 



Comments. — The best reagent for the recognition of carbon monoxide is palla- 

 dium chloride. The reaction towards this salt in solution forms the basis of the well- ' 

 known method for the quantitative determination of carbon monoxide. Although 



