128 BOTANICAL GAZETTE [AUGUST 
TABLE IV 
GENERAL METEOROLOGICAL CONDITIONS 
: rquette, 
Columbus, Ohio = —— 
PRC VATION ts 745 ee os ve a Sa 774 ft 930 ft 668 ft 
ae op WG an ee 3I yrs. 25 yrs. 33 yrs. 
Mean seantad temperature in degrees F. 
Re as See See eran ede rae 31 26 19 
oh i sy POS as vee ce) 51 46 37 
De hs a a 73 7° 63 
WAL se ae es ee es See 54 51 45 
ual te eee ee ec reese 2 48 41 
Apsonite mami. 6 sao Cee. ees 104 Io 108 
Aleonice MINN oo oa, oe eS hk —20 —24 we 
RBUINLE TONRG. eck eg foes 124 125 135 
Greatest annual ones OSS Se ae Bests alae) 118 124 
Lease aiiistranee 2 ea 89 97 
Frost, aver. date Of last in spring Secs April 16 April 28 May 15 
Frost, aver. date of first = ~ SA, 6.65 Oct. 16 Oct. 9 | Oct. 2 
] sagen in growin, ig Season. .......... 176 157 140 
Me see sonal pr saiaiea toon inches 
tee Pe US OPEC ES Poke OS 8.9 6.6 6.1 
te se a ee Bie) a0 7-3 
IRINEE et eS eco. kegs oes 10:3 10.1 9-4 
Me as 4 aan fags: 8 76 9.6 
PUA OR ia es 5 eas Oe yawns os 37.2 32.2 32-4 
depeOIMbe TASHA. 2 6 ois ee cs 51.2 47.7 42.9 
Atsolise minim ) 6. i ek 26.4 21.1 25-3 
Mean annual relative humidity.......... 79 79 80 
ING. Says OrecInItAtION. «0/0. 00. 0 ce 144 138 161 
Aver. direction of prevailing wind. . ies S.W. S.W. -W. 
Aver. minimum wind velocity. .......... eee 46 miles 
From the data in table IV, it will be observed that the seasonal 
and annual temperature decreases as one travels from the southern 
limit toward the northern center of bog vegetation. The climate 
of the region about Columbus is characterized by a milder winter 
but a relatively hot summer. The annual range in temperature 
is comparatively smaller than at Marquette, 102° F. as against 
112° F. The normal annual range is here only between 96° F. 
(35°5 C.) and —6° F. (—21°11 C.), and the greatest departure 
from the normal variation does not exceed 16° F. The monthly 
averages for only two months are at Columbus below 32° F. (0° C.), 
as against five months for Marquette. The normal number of 
days per annum with a temperature above 43° F. (6° C.), the 
factor upon which ScumpER (29) and Merriam (27) base the 
boreal limit, is at Columbus approximately 185, that is about 
one-half of the year, as against 122 days at Marquette. The 
