
TAKING THE DENSITY OF VAPOUR OF VOLATILE LIQUIDS. 455 
Mercurial column, Vapour-densities 
Millimeters. inferred therefrom. 
2°34 : : : 3°80 
2°43 ; : - 3°66 
2°50 c . . 3°56 
Another cause of uncertainty is the doubt whether the acetic acid was completely 
volatilised. Brinrav says that he applied external heat until all the liquid acetic 
acid had disappeared ; but any one who has seen Gay-Lussac’s method practised 
will know that a small bulb containing a liquid, and open at one end, will often 
contain liquid when the whole apparatus has been heated during several minutes 
above the boiling point of the liquid. 
These reasons have perhaps hindered the reception of BINEAU’s results. 
The acetic acid used in the following experiments had been purified and 
rendered free from water by repeated freezings. The portion taken for the first 
experiment had also been analysed. 
The modification of Gay-Lussac’s operation already described was employed 
in the following estimations, paraffine being used instead of water as the bath. 
A correction for the tension of mercurial vapour, according to AvoGapRo’s table, 
is introduced for the high temperatures. 
Weight of Acetic Acid = -0690 grm. 

























Observed volume : Vol. in Cub. 
in Cubic Centi- | Temperature C. abe) mn) | Cent,courected 
meters. imeters. | at 0° C. and 760 
m. m. 
Hydrogen, . . 68-05 10°4° 585°0 50460 
| Hydrogen and Acetic Acid ’ ° a : 
Vapour—Observation 1, a) peed Bee Ce ie 
Hydrogen and Acetic Acid A ° , i 
Vapour—Obs. 2, cae 130°5 163 715-0 76°897 
Hydrogen and Acetic Acid ° : 
ee Obs 26, 1207 132 6987 74-819 
Hydrogen and Acetic Acid f .RO ’ 
ee ole 4 } 115-16 1165 686-3 72-909 


Temperature. Vapour Density. 
At 186° : 
163° 6 : : 2°017 
132° : - : 2°292 
116-5° : - : 2371 
The ratio of the volume of hydrogen taken to that of the acetic acid vapour 
was about 2: 1, as inspection of the corrected volumes will show. 
It will be apparent that these numbers are quite different from those obtained 
by Canours. 
