A NEW CONSTITUENT OF THE ATMOSPHERE. 239 
The value of R is thus practically constant, and this affords a proof that the four 
last temperatures have been estimated with considerable accuracy. 
Arcon Thermometer. 







Temperature. Pressure. Volume (corr.). R. 
| en millims. i 
Series! I. 3. 1415 701-7 1:000396 2-44.46 
14:27 | 699°7 1000401 2°4366 
14-40 702°6 1:000404: 2:44.62 
99-96 906°5 1:00280 24379 
160-06 9048 1:00280 _ 24322 
—87-92 455°6 | 099756 2°4.556 
By mischance, air leaked into the bulb; it was therefore refilled. 
Series II. .} 130°58 1060°0 10037 2°6363 
185-46 1200°3 10052 2:6317 
A bubble of argon leaked into the bulb, and the value of R increased. 





Series II. . 12°05 760°9 1:00034. 2°6698 
12°61 7613 1:00034 2°6728 
248 °66 1384:0 | 1:0070 2°6717 
248°66 1376:9 | 1:0070 2°6580 
| 0:99756 26718 
—87°92 495°7 
1 

It may be concluded from these numbers, that argon undergoes no molecular 
change between — 88° and + 250°. 
Further determinations of the wave-length of sound in argon have been made, the 
wider tube having been used. In every case the argon was as carefully purified as 
possible. In experiment (3) too much lycopodium dust was present in the tube ; 
that is perhaps the cause of the low result. For completeness’ sake, the original 
result in the narrow tube has also been given. 










Half-wave-length. Temperature. 
| Date. Density. 7 ; ee Ratio. 
| In air. In argon. Air. Argon. 
| ° 
heDecs Glee alee oe ite 19:92 19°59 18:08 175 17°5 1644 
Jeeleb a eirw sites nies) 19°96 33°73 31-00 6:7 6:5 1-641 
ieee Maalery okies Mert, eros IG Oz 34°19 31:31 7°22 8°64. 1-629 
| Mins IS) 5 5 6 pe 0 19:94 | 3423 31°68 11:20 11:49 1659 | 


The general mean of these numbers is 1643; if (3) be rejected, it is 1648. In 
the last experiment every precaution was taken. The half-wave-length in air is 
the mean of 11 readings, the highest of which was 34°67 and the lowest 34:00. 
They run :— 
