456 DR LYON PLAYFAIR AND MR J. A. WANKLYN ON A MODE OF 
At 130° Canours obtains a specific gravity of 3:105, whilst at 132° C. we find 
the number 2°292. 
It would seem, therefore, that mere admixture of acetic acid vapour with 
hydrogen is sufficient to alter the vapour-density belonging to it. 
A second experiment appears to indicate that this alteration is dependent 
upon the proportion of diluent gas employed. 
Acetic acid taken = ‘0820 grm. 



















Observed volume ; Vol. in Cub, 
in Cubic Centi- | Temperature C. Pressure in Cent. corrected 
meters. Millimeters. | at 0° C. and 760 
m. m. 
Hydrogen, . . 51-5 12:5° 546 8538 
Hydrogen and Laer ae ; nae 
servation 1, 0%) 128-92 212°5 693-5 66-176 
Hydrogen and arpSr os f g 
servation 2, } 123-04 194 | 699-7 66:243 
Hydrogen and Bence: / al 
servation 3, } 119°1 182 695°5 65°418 
Hyd: dv —Ob- 3 
iene oe } 114-14 166-5° 668°6 62-393 
Hyd dV — Ob- 
Serene: if sciee ae 102-66 130-5° 672-7 61:496 
d —Ob- 
se ae eg atin’ 9 an 98-21 119° 662-0 59-594 
Temperature. Vapour Density. 
Pa ea . ; 5 2:060 
194° : : : 2°055 
182° ; : : 2:108 
166°5° ; A : 2-350 
130-5° ‘ : ‘ 2-426 
119° . ; : 2-623 
In this series of observations the ratio of the hydrogen to the vapour was 
rather less than one of hydrogen to one of vapour. 
From these results it is manifest that the specific gravity of acetic vapour can 
be altered by mixing it with different proportions of hydrogen. This fact, if it 
stood alone, would indicate that acetic acid is physically abnormal. If, however, 
the phenomenon were purely physical and not chemical, we should expect to 
find that dilution with a gas would alter the specific gravity at all temperatures. — 
Further research has brought out that at low temperatures the specific gravity of 
acetic acid vapour is invariable, or only slightly variable—a fact which points — 
towards chemical change. i 

