184
Table IV exhibits the tension of vapour expressed in inches of mercury at the Observatory and at the Peak, the latter being the mean of observations made at 10 a,, 4 p. and 10 p., and the excess of the hourly values above the mean at the Observatory. The daily variation, as was to be expected from a coast station, is small, but there is less vapour in the air in the morning than in the evening. In summer the daily variation is nearly insensible.
The monthly extreme ranges in vapour tension (at 10 a, 4p. and 10 p.) are exhibited in Tables XVI and XVII. They were greatest in November.
The
The annual variation of the vapour tension was about the same as in the previous year. maximum monthly mean occurred in June at the Observatory and in July at the Peak, the minimum in February at both stations. The mean relative humidity was greatest in April at the Observatory and in May at the Peak and was least in November at both stations.
Table V exhibits the total number of hours of bright sun-shine. The daily maximum fell about 11 a. and there was a little more sun-shine in the forenoon than in the afternoon,-just the opposite of the previous year. The monthly minimum occurred in February and the maximum in October. The minimum in percentage of possible duration occurred in February and the maximum in December. The record on days on which the sun shone without interruption from sunrise to sunset having been compared with the time during which the sun was above the horizon, it was found that the sun is not strong enough to make a trace till 0.4 hours after its time of rising or before setting, calculated without taking refraction or diameter into account, and the total possible durations shown in the last but one column have been calculated by taking this into account. It was owing to the uncertainty of this quantity, that the percentage of possible duration was not exhibited in last year's report. It would obviously have been wrong to calculate on the supposition, that the sun was strong enough to mark the card from sunrise to sunset.
Table VI exhibits the total hourly rainfall. It appears, that there is a regular daily variation, the maximum falling about 9 a. and the minimum about 5p. June was the wettest month and November the driest. The greatest falls of rain are exhibited in Table XVI. It will be remarked that 12.63 inches of rain fell on the 12th June at the Observatory and 14.50 at the Peak.
Table VII exhibits the number of hours, during portion of which, it rained. The data in this table should be used only for comparison, the correct total duration of rain being exhibited in Table XI. It appears from this table, that it rains more often about sunrise than about sunset.
These tables were omitted in last year's report, as conclusions concerning the fall of rain are occasionally drawn on insufficient data. They are exhibited below and confirm the remarks made above.
0.065 0.093 0.842 0.250 0.063 0.625 0.386 0.085 0.495 0.443
Total Hourly Rainfall during ten months of the year 1884.
Month.
1 a. 2 8. 3 a. 4 2. 5 a. 6 a. 7 a. 8 4. 9 4. 10 a, 11 a. Noon, 1 p.
2 p.
3 p. 4 p.
5 p-
6 p.
7 p. 8 p. 9 p. 10 p. 11 p. Midt. Sum.
5.827
March,
April,
May,.......
June,
July,
0,132 0.070 1.375 0.268 0.092 0.123 0.099 0.015 0.345 0.009
.250 .290 .390 .225 .235 .117 .185 .182 1,278 .220 0.895 0.065 0,030 0,015 .030 .064 $35 .055 .010 .030 .: .025 185 150 5.261
.035 .075 .025 .135 .240 .505 .795 .080 .020 .084 .800 1,215 .045 .340 ,810 ,520 .675 1.265 715 .280 .180 .010 .145 045 9.089
.145 280 .230 .370 .315 2.145 .790 940 160 .230 .235 .315 355 1,515 1,005 .115 .145 ,225 .805 345 .155 .065 .050 100 11,035
.075 .185 .210 510 1.295 1.020 .920 2.085 1.145 .160 .560 .740 .790 .720 .255 .310 .175
115 .305 .830 400 .115 .015 .140 18.075
August,
.630 .565 1.390 .615 1.005 .825 .400 .250 .265 .725 250 .455 .020
.165 .265 .905 .250 .170 1.070 .435 .915 .355 10.815
September, ..... 1.105 1.280 1.070 .700 .340 .220 .250 .445 .420 .125 .040 .475 .080 .315 .325 .690 .470 .975 1.195 .520 100 190
October,
November,
December,
.110 .335 150 .070 .030 .010 .005 250 .070
.730 .285 .145 .015 .090 .100 ,100 .105 .010
.050 .010 .025 .06.5 .015 .025 .040 .005 .075 .125 .135 .135 .210 .035 .015 .010
.380 .660 12.370
.015 .120 .175 .165 3.085
.100 .170 .050 .040 .140 1.495
Sums....... 1,902 3.155 4.040 3.733 3.177 5.170 5.700 4.402 3.768 1.218 4.120 3.480 2.110 2.995 2,595 2.057 3.007 3.895 3.295 2.900 2.486 1.095 1.500 2.198) 72.002
Month.
Number of Hours, during portion of which it rained, during ten months of the year 1884.
1a. 2a. 3 a. 4 a. 5 a. Ga, 7a, 8 a. 9 a. 10 a. 11 a. Noon. I p. 2p. 3p. 4p. 5p. 6p. 7p. 8p. 9p. 10 p. 11 p. Midt. Sum,
March,
3 2
April,
5
3
May,
3 4 +
June, ............
5
3
July,
August,
September,
5
October,
November,........................
December,
120 10 10 10❤N:
24412 10 10+
5
4
6
- 10 03 01 00 CAP W
1
3
1
6
5
5
4
5
1
21+042-2:
60 10 10 45 00 10 05
2
2010 10 NNN!
1
4
5
7
8
5
2000 10 0 = 0;
∶41446313
4 3
1
2
5
+62-2;
3
2
1
2 I
3
1
PUUT RA 1909 1
39 40 15 4 6 2
QHHH
2 2 1
3 1 1 2
6 8 4
3
6
4
5
1
2
2
2 2 2 2
2 1 1 1 1
2
1
LINGAUNW
4 2
1
::
2
2
1
2
1 2
1 2 1
Sumis,... 28 31 87 35 34 35 33 32 35 34 26 31
61 60 61 62 61 – ~~~
EN 60 HID LO HON ON 40
2
42
77
86
102
129
85
69
37
23 19 20 27 23 23 20 24 27 19 19 30 665
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