THOMPSON. — ON THE EQUILIBRIUM OF THE SYSTEM. 445 



.000280 X .0821 X 285 X 760 X 90.0 n ni 

 ■'•■Pco = - 19.9 X 663 -=0.34 mm. 



On opening the furnace a larger amount of powder than any other 

 experiments here given was found on the walls. This, taken in con- 

 nection with the small pressure found and the experiments referred to 

 in the Introduction seem to indicate that at this temperature the car- 

 bon monoxide was removed by calcium coming from the decomposition 

 of carbide. 



It is true that this equilibrium was really approached from the side 

 of too little carbon monoxide, but as the velocity of the reaction is the 

 same in both directions at equilibrium, this cannot account for the low 

 pressure of carbon monoxide. 



Experiment 6. 



The hydrogen used in the following experiments was generated 

 electrolytically on platinum electrodes dipping into sulphuric acid 

 of 1.2 specific gravity. The cathodes were contained in a porous cup 

 closed at the top by a cork stopper covered with paraffin, through 

 which projected glass tubes, into which the electrodes were sealed. 

 There was also a tube through which hydrogen could escape. The 

 porous cup stood in a small battery jar. The hydrogen tube was con- 

 nected to a mercury manometer so that the pressure in the cathode 

 compartment could be kept from 0.1 to 1.0 centimeter above the 

 atmosphere, thereby preventing air from leaking in. In Experiment 6 

 only one such electrolytic cell was used, but for the last two experi- 

 ments another cell was connected in series with the first, thus requir- 

 ing only half the time for filling the furnace. The hydrogen first 

 passed through a soda lime tube, then the hot copper gauze used in 

 the previous experiments, then two soda lime towers and phosphorous 

 pentoxide tube. Hydrogen was passed over the hot copper for at 

 least half an hour before any was let into the furnace, in order to 

 sweep out the air in the tube. The object in using electrolytic hydro- 

 gen was to show that the above gains in weight were not due to im- 

 purities in the hydrogen generated from zinc and hydrochloric acid. 



The carbon monoxide used in the following experiments was gen- 

 erated by allowing formic acid to drop from a separatory funnel into 

 concentrated sulphuric acid. 



In order to see if all the carbon monoxide was absorbed by the two 

 Liebig bulbs containing cuprous chloride in the following experiments 

 a second absorbing apparatus similar to the above was used with one 

 Liebig bulb in place of two. This was filled with a 3 per cent solution 



