440 PROCEEDINGS OF THE AMERICAN ACADEMY. 



apparatus. The experiment was continued till 4.00 p. m. to make sure 

 equilibrium had been reached. The method used to determine the 

 small quantity of carbon monoxide present in this and all the following 

 experiments was to draw about half the gas in the furnace through 

 two Liebig bulbs sealed together and filled with cuprous chloride solu- 

 tion. These were tilted at an angle so the gas bubbled through the 

 liquid on leaving each of the five spheres of which a Liebig bulb is 

 composed. The gas then passed a column seven centimeters long of 

 soda lime and another similar one of phosphorous pentoxide. This 

 whole apparatus was made entirely of glass closed by two glass stop- 

 cocks. The bulbs, in which the air was displaced by hydrogen, were 

 hung in the balance case by a platinum wire the day before the final 

 weight was taken. The air in the balance case was dried by two 

 beakers of sulphuric acid and the temperature was read from a ther- 

 mometer in the case. The volume of the bulbs was determined by the 

 bottle method for specific gravity, in which a large desiccator took 

 the place of the bottle. This was necessary in order to be able to 

 reduce the weighings to vacuo. From the total weight in grams of 

 carbon monoxide absorbed the number of moles is formed by dividing 

 by 28, the molecular weight of the gas. This, however, gives only a 

 fraction of the total amount in the furnace. The total amount is cal- 

 culated as follows. If iii = the total number of moles in the furnace 

 ' before any gas is removed, » 2 the number after a certain amount had 

 been drawn off through the absorption bulbs, p x = the pressure in the 

 furnace when the absorption began and p 2 the pressure at the end, 

 then 



p 2 v — n%RT$ 



where v equals the volume of the furnace. The temperatures were 

 equal to those of the water surrounding the furnace and were made 

 equal to each other at the start and finish. 



Therefore — = — 



n 2 P n - 



also ih — » 2 — m 



if m = the number of moles absorbed. 



Solving «i = 



Pi 



