HYPOTHESES BEARING ON CLIMATIC CHANGES 661 
l1l—continued. 
Whenss— 10>¢10° “ 5-8 8O055 es 
Witten bee 3O° V5 —— O02 ¢ 
Wihene— id e< Toe senna me 
When — 07 >< bo° V5 — 6822.0 OY 
Wihente——z0p~ To" © VZe— 6282-0 e 
When ¢ia—a5ec res 5 5005.4 e 
When. 300% 10° =“ V5 — OS. 7; uf 
When += 40 XI10° “ Vy —) s4o2.4 at 
When. — Gor roo * Vy’ = 3552.0 ss 
When — too. re® ' < bg = 2668.3 és 
Whenw—a5oecro i —— 207 2A as 
Whenrm— cope toe  “ 07, ae 
When —jiogh ator. Wa .0 
V 2g 7? 41? x Log. 1 2 gr? = 7.4508144 
le = : 
Vex z* 
t= 1 247 — Sono" Log. HT 6.1914987 
7? 
The molecular velocities vary with temperature. The fol- 
lowing table computed for me by Mr. A. W. Whitney exhibits 
these velocities for temperatures ranging from zero to 4000° C.: 
TV: 
TABLE OF AVERAGE MOLECULAR VELOCITIES FOR VARYING TEMPERA- 
TURES, IN CENTIMETERS PER SECOND, STANDARD PRESSURE. 
°° 100° 1000" 1250" 500° 2000° 3000° 4000° 
He 169611 198257 367258 400428 432243 489410 587282 671029 
H,O 56522 66067 122054 133501 144042 163093 195707 223619 
CO, 33259 38876 71819 78556 84759 695965 115160 131580 
O, 39155 45768 84551 92482 99786 112983 135576 154907 
N, 41735 48784 90122 98574 106359 120425 144508 165115 
The molecules of a gas of a given temperature have a mean 
velocity, but this does not express the actual velocity of the 
individual molecules. By their interaction upon one another the 
velocities of some are depressed, the limit being zero, and the 
velocities of others are increased, the limit being infinity. 
