382 
Transactions of the Royal Society of South Africa. 
4. Some Details of Rainfall. 
Table A. — Mean Hourly Variation of Rainfall at Kenilivorth. 
Hour 
(ending-) . 
I 
Frequency 
(times). 
13 
Quantity 
(inches). 
•64 
Rate 
(inches) 
•049 
II 
12 
•55 
•046 
III 
11 
61 
•055 
IV 
10 
•48 
•048 
V 
11 
•47 
•043 
VI 
11 
•43 
•039 
VII 
9 
■34 
•038 
VIII 
10 
•34 
•034 
IX 
9 
•31 
•034 
X 
o 
o 
"26 
033 
XI 
o 
o 
•27 
•034 
Xoon 
Q 
o 
•33 
•041 
VTTT 
AIII 
1 n 
iU 
•50 
•050 
XIV 
15 
111 
•074 
XV 
18 
ro5 
•056 
XVI 
19 
1-15 
•061 
XVII 
19 
1-52 
•080 
XVIII . 
19 
127 
•067 
XIX 
18 
•94 
•052 
XX 
18 
105 
•058 
XXI 
18 
101 
•056 
XXII 
16 
•78 
•049 
XXIII . 
15 
•69 
•046 
Midnight . 
14 
•78 
•056 
Year 
319 
16^88 
•053 
Table A shows how the rate of rainfall varies from hour to hour at 
Kenilworth (Kimberley). It is deduced from observations made during the 
17 years 1897 to 1913 — a period in which the annual average fall was an inch 
or so less than the normal mean used in IX, 178 of the rainfall table 
The numbers under the heading " Frequency " tell how many times on an 
average it was raining during each given hour throughout the year. Thus 
for the hour ending 1 a.m. there was, 011 an average, rain on 13 days of the 
year ; for the hour ending 4 p.m. there was rain on 19 days ; and so on. 
Upon the whole there were 319 hours per annum during which rain was 
recorded, i. e. less than one hour a day. Since the average number of rainy 
days at Kenilworth is about 70, it follows that an average wet day would run 
to about 4| hours of rainfall. 
