determining the Vapour-Density of Metallic Vapours. 553 



shown in fig. 4, a set of continuous readings 5° apart was 

 obtained. The mercury-reservoir (a, fig. 4) is a long narrow 



Ffc. 4. 



tube of hard glass of known coefficient of expansion, and 

 having a carefully calibrated bore. In making a deter- 

 mination the reservoir is charged with a known weight of 

 mercury, and the bulb exhausted and sealed off as in the case 

 of sodium ; it is then introduced into the bath and supported 

 in such a position that (a) is vertical ; the height of the 

 mercury column is observed through glass windows in the 



Table IT. 



Temp. 



Density. 



Regnault & Hertz. 



Rarnsay & Young. 



40 



0-00000007 



0-00000007 



000000009 



60 



00000003 



0-0000003 



0-0000003 



70 



0-00000045 



0-0000005 



00000005 



80 



0-0000007 



0-0000008 



00000008 



90 



0-0000012 



0-0000014 



00000014 



100 



00000021 



0-0000024 



0-0000023 



110 



00000040 



0-0000039 





120 



0000060 



0O000064 



0-0000059 



140 



00000138 



0-0000147 



0000137 



160 



0000302 



00000323 



0-0000297 



180 



00000624 



0000649 



0000603 



200 



00001580 



00001236 



0-0001 L52 



220 



00002020 



0-0002271 



00002077 



240 



0-0003754 



0-0003673 





260 



0-0005830 



0005817 





270 



0*0006528 



00007257 



0007310 



280 



0-0008645 



0-0008994 



00009113 



300 



00013466 



00013547 



00013796 



305 



0-0013882 









310 



0-0016447 



00016472 



0*0016734 



.320 



00019879 



0-0019921 



0-0020180 



325 



0-0019960 









Phil. Mag. 8. 6. Vol. 4. No. 23. Sov. U»02. 



20 



