427 
ON “QUIET” DAYS DUKING THE ELEVEN YEARS 1890 TO 1900, ETC. 
and various meteorological phenomena, such as rainfall, barometric pressure, &c. It 
is thus desirable to see what was happening meteorologically at Kew finm 1890 to 
1900, and, more especially, whether there was or was not any appreciable difference 
between the meteorological data for the two groups of years 1892 to 1895 and 1890, 
1899 and 1900. 
fable XLVI. gives particulars of the mean values of the chief meteorological 
elements at Kew for the whole period, and for the two shorter groups of years. In 
the case of vapour pressure. 1891 was omitted, as reliable data were wanting for two 
01 three months of the year. Ihe mean daily range of temperature in the table is 
the mean excess of the maximum over the mininium on individual days. 
What impresses one chiefly on studying the talile, is the remarkably close agree¬ 
ment between the means for such comparatively short periods of years. Wlien the 
means for the two shorter periods difler, they are as often as not on the same side 
of the mean for the 11-year period. 
Iable XL\ I. Mean Values of Meteorological Elements at Kew. 
Period. 
M eaii 
tempera¬ 
ture for 
the day. 
Mean 
daily 
range of 
tempera¬ 
ture. 
Mean 
hours of 
sunshine 
for year. 
1 
Mean 
vapour 
pressure. 
Mean 
amount 
of cloud 
(Total = 
10 ). 
Mean 
total 
annual 
rainfall. 
Mean 
height of 
barometer. 
Average 
wind 
velocity, 
miles per 
hour. 
° F. 
° F. 
iiK-li 
iiiclies 
inches 
1890 to 1900 . . 
19-71 
13-G8 
1521 
0-287 
6-5 
22-360 
29-978 
10-21 
1892 to 1895 . . 
49-48 
13-90 
1536 
0-283 
6-2 
23-538 
29-964 
10-20 
1890, 1899, 1900 . 
49-87 
13-83 
1584 
0-288 
G * 5 
21-310 
29-970 
10-20 
1 
1 
§ 62. As results from the diurnal inequalities are more strictly paraJlel to most 
of the Kew magnetic data, mean diurnal inequalities of temperature and barometric 
pressure the two most important meteorological elements—were calculated from the 
data published by the Meteorological Office in their “ Hourly Observations.” This 
was done for groups of sun-spot maximum and sun-spot minimum years. Data for 
1900 being not yet available, 1889 was substituted in the sun-spot minimum group. 
The following were the results :— 
PtANGES in Mean Diurnal Inequalities for the Year. 
Group of year's. 
Temperature. 
Barometric pressure. 
1892 to 1895 . 
1889, 1890, 1899 .... 
° F. 
10-00 
9-70 
incli. 
-0265 
-0267 
3 I 2 
