DK. EDWARD C. EDGAR ON THE ATOMIC WEIGHT OF CHLORINE. 



11 



the oxygen with the hydrogen. When the volume of oxygen added was just below 

 half the volume of the residual gases, the tap C was temporarily closed. The gas 

 apparatus, still standing in the trough, was then attached by the inner portion E of a 

 ground-glass joint to a Sprengel pump. After the pump had been thoroughly 

 evacuated, the tap B was opened and the small remaining volume of wet hydrogen 

 and nitrogen (in no experiment exceeding 4 c.c. in volume) was sucked out of A. At 

 the same time the tap C was cautiously opened so as to allow mercury to rise slowly 

 in A and fill the whole apparatus, thus removing the last traces of gas from the 

 apparatus. 



The wet nitrogen and hydrogen passed through a coil, immersed in a freezing 

 mixture of solid carbon dioxide and ether. Most of the water vapour in the gases 

 condensed in the coil. The dried gases then passed through the pump and were 

 collected in another gas apparatus, a sketch of which is to be found on p. 193 of 

 DIXON and EDGAR'S paper. The details of the subsequent gas analysis are given in 

 full on the same page. 



The composition of the residual gases of the combustion, assuming they were 

 hydrogen and nitrogen, was thus arrived at by subtracting from the total volume 

 collected in the first gas apparatus (fig. 8) the volume of nitrogen found in the 

 second. 



10. Results of the Experiments. In the tables set out below are given the results 

 of eight experiments. Table II. contains the volumes of residual gases, in each 

 experiment, reduced to normal temperature and pressure. 



TABLE II. Volumes of liesidual Gases (Cubic Centimetres at N.T.P.). 



In Table III. are placed the weights of chlorine which escaped burning in the flame 

 and were caught by mercury in the chlorine absorption apparatus. 



TABLE III. The Weights of Chlorine Uncombiued with the Weighed Hydrogen 



(in Grammes). 



c 2 



