662 Ue, Cx CLAN IBIZIRIL IONS 
Theoretically both these limits may be reached, but extremely 
high velocities are acquired at such distant intervals as to be 
negligible. Very considerable exaltations of velocity are how- 
ever attained with sufficient frequency to be effective in dis- 
charging a large part of the gas under suitable conditions, since 
each molecule in succession is liable to acquire a high velocity. 
The following table shows the proportion of. molecules that 
_ reach or exceed the designated multiples of the average velocity 
at any instant :* 
We 
TABLE SHOWING THE PROPORTION OF MOLECULES WHICH HAVE A 
GIVEN NUMBER OF TIMES THE AVERAGE OC. VELOCITY (OR 
MORE) AT ANY INSTANT, STANDARD PRESSURE, FOR TEMPERA- 
TURES RANGING FROM OC. TO 4000°C. 
Froperioniot Times Average o°c. Velocity for different Temperatures 
t—ORCe t= 000°C. t—Ir500.C. t= 2000°G, t= 3000°C. t= 4000°C. 
Meo LO * I DoD 2.5 2.9 3.5 3.9 
to? XK IO =" 2 4.3 5.1 5.8 6.9 7.9 
Ae 2X Ome 3 6.5 7.6 8.7 10.4 II.9 
Hall SX LO? 4 8.6 10.2 itt 13.9 15.3 
On <6 1O— 5 10.8 127, 14.4 173} 19.8 
GO << 1O— 6 12.9 15.3 107 08 20.8 B27 
38 LO 7 Taso 17.8 20.2 24.2 Dei 
MND XX WO 8 7S 20.4 DBr oN DBO Sy] Bil o7/ 
10) << LO 9 19.4 22.9 25.9 Byie2 35.6 
Oa5, < 1O—-8 10) Pit sO) 25.5 28.9 34.6 39.6 
The molecules of water vapor at o° C. have an average 
velocity of 56522" per sec. The foregoing table shows the 
™This table was computed by means of the formulz given by Risteen (“ Molecules 
and the Molecular Theory of Matter,” pp. 24-28), which are based on Maxwell’s 
determinations. The high velocities assigned to a part of the molecules are mathe- 
matical deductions from data not altogether perfect, and are doubtless to be held 
with something less of firmness than would be warranted if they were experimental 
demonstrations, but in the absence of an available method of experimental demonstra- 
tion these deductions may be accepted as the nearest approximation at present 
obtainable. A brief non-mathematical statement may be found in Maxwell’s “ Theory 
of Heat,” pp. 314-316. The results require some modification for mixed gases and 
for special conditions, but this is not thought essential in this general argument. 
