LIQUEFACTION AND SOLIDIFICATION OF ARGON. 
257 


Cite || Gece ag | Pewee |Jeooemarel eerie cA lara i 
Nae: tempera- ritica oiling | Freezing | Freezing) Density | o iquid Co! our 0 
pee pressure.| point. point. j pressure.) of gas. Jat boiling} liquid. 
ae point. 
| 
| Atmos ° oS millims. 
| Hydrogen (H,) . .|{ Below. \ 200 | 2 2 2 10 ? | Colourless 
| Nitrogen (N,) —146:0 30°0 | —1944 | —214:0 60 14-0 0°885 es 
| Carbonic oxide (CO) —139'5 30°5 | —190-0 | —207°0 100 140 Fs 5 
| Angon (Ay) —1210| 50:6 | —187-0| —1896| ? 19-9 (eee i 
| Oxygen (O3) - —118'8 50'S | —182:7 P iP 16:0 1124 | Bluish 
Nitric oxide (N O) . — 93° 71:2 | —153°6 | —167-0 138 15:0 P Colourless 
Methane (CH,) . — 81:8 549 | —164-0 | —185°8 80 8-0 0:415 5 









As can be seen from the foregoing table, argon belongs to the so-called ‘‘ permanent ” 
gases, and, as regards difficulty in lquefying it, it occupies the fourth place, viz., 
between carbon monoxide and oxygen. Its behaviour on liquefaction places it nearest 
to oxygen, but it differs entirely from oxygen in being solidifiable ; as is well known, 
oxygen has not yet been made to assume a solid state 
The high density of argon rendered it probable that its ee would take 
place at a higher temperature than that at which oxygen liquefies. Its unexpectedly 
low critical temperature and boiling-point seem to have some relation to its simple 
molecular constitution. 
Note on A CoMPARISON OF THE VAPOUR-PRESSURES OF ARGON WITH THOSE OF 
OTHER SUBSTANCES. 
By Witu1AM Ramsay and SvpNEY YOuNG. 
Received February 7, 1895. 
The vapour-pressures of a considerable number of substances have been determined 
from low temperatures to the critical points, but as the critical pressure of argon is 
somewhat high, the boiling-points of very few are available for comparison through the 
whole range of equal pressures. 
The critical pressure of benzene is so slightly below that of argon that the extra- 
polation of the vapour-pressure curve through the few degrees necessary to afford a 
comparison at the critical pressure of the new element is justifiable. 
The other two substances chosen are ethyl alcohol and oxygen; 
interesting, as its vapour-pressures, like those of argon, have been determined 
by Professor OLSZEWSKI. 
In the following table the boiling-points—on the absolute scale—of argon, benzene, 
MDCCCKCV.—-A. 2. 
the second is 
