о
Rotaling Damp Ther.
2.5
0 10
92
Table III.
Dry Ther. Damp Ther.
7.5
O
10
о
O
12.5
15
17.5
20
Corn. Sets. Corrn, Scts. Corrn. Sets. Corrn. Sets. Corm. Sets. Corrn. Sets. Corrn. Sets. Corrn. Sets.
379.5
40
+0.90 +1.05
42.5
45
+0.50
-0.85 +2.01
+7.5
+2
50
+0°52 4
+0 77
7
+1.85
222924
1++0.23 + 12 +0.40 +42 5 +1 55 12
4
+1°.10
2
+3 23 7 +1 88 20 +2 .26¦ 25
+5°30 57 +12 22 +1
+62.87 + .60
3
1
52.5
-0.30 1
+0.77 9-
+1.80
55
+0.11 7
+0.71 10
57.5
60
+0.24 8 +0 31 7
62.5
65
1+0.45
67.5
+0.35
70
72.5
+0 10
75
77.5 NO
+0.03 9 +0.55 6 +0.10 2 +0 31 7 +0 35 15 +0.05 2 -0.14
It
$2.5
+0.60 6 1+0.78
+0.7 G +0.80 ୫ +0 39 +053 1-40.82 | 16 [+0.34] 22 +0.8 45 7 -0.14 13
+0.31 |40 35 (+0.35] 15 1+0.01) 26 25 9 -0..90
+1.01 10 +05 +0.05 ₤ +0.56 8
+2.05 15 +0.80 (+0.46 7 +0.87 8 +0 50 10
+1.8± 21
+1.95
+1.47 3 +2.53 7
+3.15
+2.92
5
+0 51
53 10
+0.66
.69 1
+1.75
+0.25
301 1
+0.95
+ 40
1
11
+0.74 10
+0.70
.95
2
-0.35
+0 34
12
+0.02 14
+0 39
-0.50
4
6
+0.80
14
+0.02
5
+0.20
-0.97
130 42
4
+ .22
-0.52
5
+0.18 13
-0 .63
.30
-0.13
3
:
+0 20
2
12. The following table shows the means of barometric pressure at the Observatory and at Gap Rock (32 miles S.S.W. of the Observatory) from five years' three-hourly observations (1900-1904 incl.) reduced to freezing point of water and mean sea level.
Table IV.
MONTH.
OBS. G. R.
HOUR.
OBS.
G. R.
January,
30.170
30.147
1 a.m.
29.974
29.951
February,
.222
.200
4
.951
.942
""
March,
.045
.024
7
.986
.963
April,
29.957
29.940
10
30.013
.993
May,
.872
.861
1 p.m.
29.961
.950
June,
.752
.745
4
.924
.912
July,
.737
.726 7
..953
.934
""
August,
.724
.711 10
.991
.967
September,
.873
.857
October,
.999
.974
Mean.
29.969 : 29.951
November,
30.111
30.087
December,
.170
.145
The three-hourly means are represented by the following formula, where t indicates mean time:
Observatory: 29.969 +0.019 sin (t + 7°) −0.0315 sin (2t− 28°) + 0.002 sin (3t+72°).
Gap Rock: 29.951 +0,017 sin (t—123) — 0,0265 sin (2t−32°) +0.003 sin (3t—64°).
The last term is quite uncertain. The formula show that the pressure observed at Gap Rock lags behind that registered at the Observatory and that the daily variation is smaller. This is due to friction of the mercury in the standard barometer at Gap Kock, whose tube is only half an inch in internal diameter while the tube in the barograph at the Observatory is much larger. The extremes of the bidiurnal variation occur 16 minutes too late at Gap Rock, and the diurnal variation, whose coefficient is smaller, lags still more.