326 Mixter — Experiments with Endothermic Gases. 



serving as a conductor. The result was a brilliant violet light 

 and the separation of a little more carbon. The primary cur- 

 rent had, however, broken the filament so that on connecting 

 again with a coil in action sparks passed, but soon ceased. The 

 primary current then gave the same result as before. The 

 amount of cyanogen decomposed was small, for of the 100 cc 

 taken only l cc was not absorbed by potassium hydroxide after 

 the experiment. 



Experiment #. — Cyanogen was condensed in the apparatus 

 fig. 2 until a portion liquefied, and the wire was heated white 

 hot by a current from a battery. A slight fog appeared but 

 there was no separation of carbon throughout the gas, and 

 there was no explosion. The result was the same at lower 

 pressures. Finally the platinum wire was melted in the gas at 

 the pressure of liquefaction, but there was no explosion nor 

 any considerable decomposition. A thin coating of carbon had 

 formed on the wire. 



Nitrous Oxide. 



Experiment 1. — The apparatus, fig. 1, was filled with 72 cc of 

 pure dry nitrous oxide, and the gas was condensed to 6 CC and 

 sparked. There was no explosion. Faint red fumes appeared. 

 On lowering the pressure after the sparking to that of the 

 atmosphere, the gas showed increased volume but not 50 per 

 cent, as would have been the case had the dissociation been 

 complete. 



Experiment 2. — 100 ce of gas condensed to 5 CC and finally to 

 3 CC were sparked for some time. There was no explosion and the 

 volume at the close of the experiment was less than 150 cc . 



Experiment 3. — 70 cc of nitrous oxide were condensed to 5 CC 

 and sparked. The result was the same as in the preceding 

 experiments. 



Experiment Jp. — 100 ce of nitrous oxide condensed to 10 cc 

 were sparked. There was no explosion. 



In the above tests the platinum electrodes were 4 mm apart 

 and the spark used was fairly strong and had a length in air 

 of 3 cm . 



Nitric Oxide. 



Experiment 1. — Dry nitric oxide was sparked at pressures 

 varying from 12 to 20 atmospheres. There was no explosion, 

 but the gas became reddish. 



Experiment 2. — 100 cc of dry nitric oxide were condensed to 

 10 cc . The spark and electrodes were as described under nitrous 

 oxide. The first spark through the gas produced a small flame 

 between the electrodes. The sparking was continued only a 





