Observed. 



Calculated 



22 



22 



4-9 



44 



6-5 



6-6 



8-8 



8-8 



10-7 



110 



125 



130 



13-8 



15-4 



145 



17-6 



150 



190 



156 



220 



16-2 



24 2 



16-8 



264 



17-5 



28-6 



18-2 



30-8 



190 



330 



200 



352 



20-0 



37-4 



20-2 



396 



21 



41-8 



21-0 



440 



186 Prof. Tyndall on the Absorption and 



Table VI. — Bisulphide of Carbon. 

 Unit-measure | a cubic inch. 

 Absorption. 



Measures. 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11 



12 



13 



14 



15 



Ifi 



17 



18 



19 



20 



As far as the sixth measure the absorption is proportional to 

 the density ; after which the effect of each successive measure 

 diminishes. Comparing the absorption effected by a quantity 

 of vapour which depressed the mercury column half an inch, 

 with that effected by vapour possessing one inch of tension, the 

 same deviation from proportionality is observed. 



By mercurial gauge. 

 Tension. Absorption. 



\ inch 14-8 



1 inch 18-8 



These numbers simply express the galvanometric deflections, 

 which, as already stated, are strictly proportional to the absorp- 

 tion as far as 36° or 37°. Did the law of proportion hold good, 

 the absorption due to 1 inch of tension ought of course to be 

 29-6 instead of 18-8. 



Whether for equal volumes of the vapours at their maximum 

 density, or for equal tensions as measured by the depression of 

 the mercurial column, bisulphide of carbon exercises the lowest 

 absorptive power of all the vapours which I have hitherto ex- 

 amined. For very small quantities, a volume of sulphuric ether 

 vapour, at its maximum density in the measure, and expanded 

 thence into the tube, absorbs 100 times the quantity of radiant 

 heat intercepted by an equal volume of bisulphide of carbon 

 vapour at its maximum density. These are the extreme limits 



