Atmospheric Pressure. 
281 
TABLE XIX. — Extreme Readings of the Barometer for each Month ; Extreme Mean Daily Heights 
for each Month ; and Extreme Diurnal Ranges for each Month, together with the Ranges and 
Means of the Extremes. 
Extreme Readings. 
Month . 
Hig] 
lest. 
Lowest. 
Range, 
Mean. 
d. 
h. 
in. 
d. 
h. 
in. 
in. 
in. 
January 
19 
0 
30-196 
13 
2 
27-837 
2-359 
29-016 
February 
7 
2 
30-063 
3 
2 
28-770 
1-293 
29-416 
March 
8 
0 
30-158 
30 
18 
28-969 
1-189 
29-563 
April 
23 
20 
29-836 
1 
8 
28-953 
0-883 
29-395 
May 
1 
0 
30-200 
27 
6 
29-108 
1-092 
29-654 
June 
14 
20 
29-996 
8 
18 
28-618 
1-378 
29-307 
July 
11 
2 
30 030 
29 
6 
29-135 
0-895 
29-582 
August 
September 
12 
10 
30-048 
22 
4 
29-065 
0-983 
29-556 
22 
22 
30-368 
29 
18 
29-385 
0-983 
29-876 
October 
19 
0 
30-161 
28 
0 
28-415 
1-746 
29-288 
November 
29 
10 
30-165 
21 
20 
28-647 
1-518 
29-406 
December 
28 
0 
30-207 
5 
4 
29-462 
0-745 
29-834 
Extreme Daily Means. 
Extreme Diurnal Ranges. 
Highest. 
Lowest. 
Range. 
Mean. 
Greatest. 
Least. 
d. 
in. 
d. 
in. 
in. 
d. 
in. 
d. 
19 
30-169 
13 
28-022 
2-147 
29-095 
9 
1-044 
2 
0-060 
7 
30-026 
3 
28-914 
1-112 
29-470 
4 
0-660 
25 
0-047 
8 
30-125 
31 
29-063 
1-062 
29-594 
30 
0-669 
8 
0-053 
18 
29-791 
1 
29-026 
0-765 
29-408 
&} 
0-509 
11 
0058 
1 
30-184 
27 
29-141 
1-043 
29-662 
3 
0-400 
15 
0033 
12 
29-983 
9 
28-838 
1-145 
29-410 
10 
0-597 
12 
0-021 
11 
29-999 
29 
29-237 
0-762 
29-618 
17 
0-519 
13 
0-025 
12 
30-022 
3 
29-130 
0-892 
29-576 
21 
0-510 
11 
0-034 
23 
30-323 
30 
29-500 
0-823 
29-911 
11 
0-412 
0-029 
19 
30-105 
28 
28-586 
1-519 
29-345 
28 
0-724 
25 
0-030 
14 
30-080 
22 
28-963 
1-117 
29-521 
22 
0-655 
2 
0-083 
18 
30-187 
5 
29-545 
0-642 
29-866 
4 
0-481 
18 
0-044 
Extremes of Atmospheric Pressure for 1843. 
September 
22 d 22" 
= 30-368 
January 
13 d 2 h 
= 27-837 
September 
23 d 
= 30-323 
January 
13 d 
= 28-022 
December 
- 29-963 
January 
= 29-358 
mean = 29-102. 
mean = 29-172. 
•605, mean = 29-660. 
The greatest diurnal range of pressure occurred January 9 d , = 1-044. 
The least June 12 d , =0-021. 
The greatest range of pressure for a month occurred January 13 d — 19 d , = 2-359. 
The least December, - 0-745. 
The greatest range of mean daily pressure for a month occurred January 13 d — 19 d , = 2-147. 
The least December, = 0-642. 
The mean of the highest and lowest readings in the year is 0-507 in. less than the mean for the year ; the 
mean of the highest and lowest daily means is 0-437 in. less than the mean for the year. If we compare 
similarly the means of the highest and lowest readings and daily means in each month with the monthly means, 
we obtain the following results : — 
Monthly Means minus Mean of Highest and Lowest Readings in each Month 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. 
in. in. in. in. in. in. in. in. 
+ 0-341 +0-083 +0-099 +0*092 -0-034 +0-312 +0-053 +0-100 
Nov. 
0-059 
Dec. 
0-113 +0-065 +0-128 
Monthly Means minus Mean of Highest and Lowest Daily Means in each Month. 
Jan. Feb. March. April. May. June. July. Aug. Sept. Oct. Nov. 
in. in. in. in. in. in. in. in. in. in. in. 
+ 0-262 +0-029 +0-068 +0-079 -0-042 +0-209 +0-017 +0-080 +0-024 +0-056 -0-050 +0-096 
MAG. AND MET. OBS. 1843. 4 B 
Dec. 
in. 
