2 DE. EDWARD C. EDGAR ON THE ATOMIC WEIGHT OF CHLORINE, 



boro-silicate glass bulb : the chlorine, prepared by electrolysing fused silver chloride 

 in a Jena glass vessel, was weighed as a liquid in a thick-walled boro-silicate glass 

 bulb; These bulbs were attached to a quartz combustion vessel, which was also 

 Connected with a quartz tube and with a steel bomb and a pump. After a thorough 

 evacuation of the whole apparatus, the combustion vessel was filled with hydrogen 

 from the heated palladium bulb, and the chlorine was ignited by a spark at the tip of 

 a quartz jet and continued to burn in the atmosphere of hydrogen, with a fine needle- 

 shaped flame, until nearly all the chlorine weighed had been burnt. The hydrogen 

 chloride, immediately after its formation in the flame, was condensed as a snow-white 

 solid by liquid air surrounding a limb of the combustion vessel ; and a little chlorine, 

 which had escaped burning, was also solidified. At the end of the combustion, the 

 residual gas in the combustion vessel was extracted by the pump and subsequently 

 analysed ; it proved to be practically pure hydrogen. 



Then the snow-white hydrogen chloride was allowed to pass through a quartz tube 

 filled with mercury vapour, and the purified gas was condensed in a steel bomb 

 immersed in liquid air. It "was successfully weighed in three experiments ; in two 

 other experiments the gas was absorbed by water and weighed as aqueous acid. 



The balance was made specially for this work by Oertling. Each piece of 

 apparatus weighed was tared with another of the same material and of very nearly 

 equal volume and weight, and the small weights used in the weighings were reduced 

 to a vacuum standard. 



Below are set out the corrected weights of hydrogen and chlorine burnt in eight 

 experiments and the weights of hydrogen chloride caught in five. 



TABLE I. 



If the atomic weight of hydrogen be taken as 1-00762, the mean values for the 

 atomic weight of chlorine calculated from the numbers in the table above are 

 35'4620-0008 and 35'4610'0009. 



