140 
PROFESSORS W. RAIRSAY ARE S. TOUXG 
temperature as the alcohol. The best method of comparison appears to be to reduce 
the results of other observers to true densities, and to read from the curve constructed 
from our observations the densities at the corresponding temperatures. The most 
reliable results appear to be the following (the references are the same as before):— 
Observer. 
Specific gravity — 
Density or — 
Result from our curve. 
Bruhl . 
•8044 2074 " 
•8044 at 20° 
•8035 
Zander . 
•8069 I 77 O" 
•8068 at 17° 
•8059 
Ltnnejiann. 
•8066 I. 57 IV 
•8059 at 15° 
•8076 
Perkin. 
•80883 1 . 5715 ° 
•8082 at 15° 
•8076 
•80247 2572 . 5 ” 
•8002 at 25° 
•7995 
SCHIFF . 
•7366 97°-l/4° 
•7366 at 97°-l 
•7353 
It will be seen that our results are in close agreement with those of other observers ; 
they are very slightly lower than most of the others, but at 15° our result is rather 
higher than Linnemann’s. 
ConsUints at High Temgyeratures .—Four different amounts of propyl alcohol were 
employed for these determinations. The vapour-pressures and the orthobaric volumes 
and compressibilities of the liquid were determined with the largest quantity. A, the 
weight of which was calculated from its volume and specific gravity. The smaller 
cjuantities, B, C, D, were employed for the determinations of the volumes of a gram of 
vapour. The weight of B was ascertained by comparisons of its volume with that 
of A under similar conditions of temperature and pressure. The weight of C was 
obtained in a similar manner from tliat of B, and the weight of D similarly from that 
of C. 
Weight of quantity A.—The actual volumes of this quantity at various tempera¬ 
tures were plotted on sectional paper, and a curve drawn through the points ; the 
volumes at 0° and 10°'72 were read off, and the weight calculated from the densities 
at those temperatures. 
Volume of A at 0° . . 0'32335. Volume of 1 grm. at 0° . . 1'22056. 
Volume of A at ]0°'72 . 0'32675. Volume of 1 grm. at 10°'72 . 1'23306. 
Grm. 
Weight from volume at 0°. 
0-26492 
Weight from volume at 10°'72 . . . 
0-26499 
Mean. 
0-26496 
Grm. 
Weight of B. Mean of numerous comparisons with A 
0-03763. 
Weight of C. Mean of numerous conqiarisons with B 
0-006015. 
Weight of D. Mean of numerous comparisons with C 
0-005180. 
