368 Transactions of the Boyal Society of South Africa. 
Section (b).— This condition prevailed upon 8 occasions, and on 6 of 
them no rain followed ; in all cases the wind was easterly ; on both the 
remaining days the falls were below 0'05 in. 
Prediction. — Dry weather. 
Section (c). — This happened upon 8 occasions, and on none of them 
did rain follow ; wind was easterly on each of them. 
Prediction. — Dry weather. 
SUB-GEOUP (B). 
Two reasons can be assigned for this condition ; either a depression is 
coming up from the south or a local secondary is deepening over the land. 
In each case an area of high pressure exists to the west, which is against 
the formation of rain clouds. At the same time a depression from the 
south has a tendency to bring rain, but one deepening over the land has 
the reverse effect. These two conditions can be separated when the 
actual readings of the barometers are examined, for if that at L'Agulhas 
be lowest there is no doubt whatever about there being a depression 
advancing from the south, but if the lowest reading be at Clanwilliam 
it is more than likely that a secondary is deepening over the land. 
DIVISION (1). 
Section (a). — During the 5 years under review, rain followed within 
24 hours at the Eoyal Observatory on 13 occasions out of 19 ; wind was 
from some point of west upon 14 occasions. 
Prediction. — Wet weather. 
Section (b). — This condition occurred upon 8 occasions, rain following 
upon 4 of them ; on all but 1 day the wind was from some point of west. 
Prediction. — If due to a winter type depression, then rain to 
follow ; but if it be a general deepening over the land look out for 
dry weather. 
Section (c). — This condition existed upon 7 occasions, and on 3 of these 
rain followed ; the rain bringing winds were westerly, but the dry weather 
was divided equally between west and east winds. Only on 1 occasion 
was the fall over 0-05 in. 
Prediction. — Dry weather. 
DIVISION (2). 
Section (a), (b), and (c). — During the whole 5 years such a condition 
never occurred. 
