82 W. Hopkins on Changes of Climate. 
' 
annual temperature. This tract may be considered as compris 
ing the whole of Central Europe, together with its western pot 
tion from the Pyrenees to the southern shores of the Baltic. It 
is the region in which the geologist is more especially interested 
in tracing the climatal influences of changes in the configuration 
of the earth’s surfacc. I shall therefore endeavor to ascertain from 
more general considerations the probable effect of an extended 
ocean on the winter, the summer, andthe mean annual = 
tures of the region in question. 
17. For this purpose I have deduced from Dove’s map the fol 
lowing results respecting these temperatures for the 20th, 30th, 
40th and 50th parallels of latitude in both hemispheres. 
result given for January is the mean of the January tem 
for all places situated under the corresponding parallel of latithil 
and each result for July is a similar mean for the July temperatures. 
The mean of these is assumed to be the approximate value of 
mean annual temperature of the different parallels respectively : 
ae 
Mean Annual Temperatures of different Parallels of Latitude. 
Diff. 
Lat.=20° N Lat.=20° 8. Dif, 
cata mean temp. ‘ 08 F. t 14° aay mean temp. 2 U F. t 9? 
"oe annual temp. . . 5b Mean annual temp. . 445 oe 
Lat.=30° N. Lat.=30° 8. s 
cota mean temp. . F. i 20° January mean temp... ‘ F, } 49° 
Mean annual temp. . 68 Mean a temp. . 69 ie 
Lat=40° N. Iat=40°S. 
Jay mean temp. af F, i 35° JanUAEy mean temp. 3 F. b 9° 
Mean wide temp. 545 Mean annual temp. . cee 
Lat.=50° N. Farxianp Istanps.* Lat=50° 8. ; 
ja mean temp. a8 F. } 46° fanny mean temp. a% ' 18° 
Mean nell temp. . 39 Men siding temp. . rae 
We may first remark the striking equality of mean tem peratt ures 
in correspondin 
g par 
the 40th ts of latitude. 
the above 
rallels north and south of the equ 
The small differences indicated by 
mbers are not to be regarded, ete they lie within 
uator as far as 
the limits of error to which the numbers themselves must neces 
sarily be subject. In the latitude of 50° N. the severe wintereud 
of Eastern Asia and that of the central portions of the North 
American continent reduce the mean Rice to more than 4 
sane 
that tho te 
2% 
Sass Es ag ee 
