PROFESSOR GRAHAM ON THE MOTION OF GASES. 
373 
6, Hydrosulphuric Acid. 
This gas was evolved by the action of hydrochloric acid upon the sulphide of anti- 
mony ; it was washed with water, and afterwards dried by passing over chloride of 
calcium. 
(1.) Hydrosulphuric acid was first transpired by a short length of capillary M, of 
8’7fi inches, into the six-pint aspirator-jar, through the usual range of 28'5 to 23"5 
inches of the attached barometer: thermometer 62°, barometer 29’674 to 29'652 
inches. The following observations were made in the order in which they are related : 
— times of air, 999 and 1001 seconds; of hydrosulphuric acid, 692, 692 seconds; of 
hydrosulphuric acid gas saturated with the vapour of bisulphide of carbon, 682, 680 
seconds ; and lastly, of hydrosulphuric acid again, 685, 685 seconds. 
The ratio of the first hydrosulphuric acid to air is 0‘691, and of the second 0’685 ; 
the ratio of the hydrosulphuric acid saturated with the vapour of bisulphide of carbon 
is 0'681, or differs little from that of hydrosulphuric acid itself; showing that these 
two sulphur compounds nearly coincide in transpirability. Multiplying these results 
by 0‘9, we have — 
Transpiration time of hydrosulphuric acid (1) .... 0*6219 
Transpiration time of hydrosulphuric acid (2) .... 0*6165 
Mean transpiration time 0*6192 
This gas proved less uniform in its rate in different experiments than I have gene- 
rally observed for other gases, at least with the present capillary. 
In a repetition of the preceding experiments, thermometer 60°, barometer 29*860 to 
29*858, the times observed were for air, 982, 983 and 981 seconds ; for hydrosulphuric 
acid saturated with bisulphide of carbon, 659, 659, 659 seconds ; and for hydrosul- 
phuric acid alone, 663, 664 seconds ; which give the ratios to air of 0*671 1 and 0*6746. 
And multiplying by 0*9, we have — 
Transpiration time of hydrosulphuric acid 0*6071 
(2.) Hydrosulphuric acid gas was also transpired by means of the long capillary M, 
52*5 inches in length, into the two-pint aspirator-jar. It was then supplied from a 
wash-bottle with a relief tube as in the experiments upon cyanogen and ammonia, 
without being retained over water. Thermometer 59°*5 Fahr., barometer 29*550 to 
29*292. 
The times of air were 1 134, 1134 seconds ; of hydrosulphuric acid, 782, 780 seconds ; 
of hydrosulphuric acid carried through a column of bisulphide of carbon 2^ inches in 
depth and kept at the fixed temperature of 59°*5, 773, 771, 772 seconds. These give 
the ratios to air, of 0*6887 for hydrosulphuric acid, and 0*6808 for hydrosulphuric 
acid saturated with the vapour of bisulphide of carbon at 59°*5. Also, multiplying 
by 0*9,— 
Transpiration time of hydrosulphuric acid 0*6198 
MDCCCXLIX. 3 c 
