AGRO-GEOGRAPHICAL CONDITIONS IN SOUTH AFRICA. 13 



and December, at a time when not only most susceptible to 

 hail, but also when hailstorms are most prevalent. 



Snow, unfortunately, is of infrequent occurrence and is 

 usually confined to the mountainous districts, e.g., Basutoland 

 and Barkly East. 



Length of Growing Season. — This is affected by the 

 days of the commencement of the rainy season, the intervals 

 between killing frosts, the altitude and, of course, the latitude. 



In some parts the commencement of the rainy season is 

 frequently so late as to delay agricultural operations very con- 

 siderably, and the growing season becomes a short and unsatis- 

 factory one. This is especially the case in central and north- 

 western Transvaal. 



The modification of the length of the growing season by 

 frosts is often a serious one, more particularly to the horticul- 

 turist, but also to the farmer dependent on summer crops. In 

 the Karroo, at Colonies Plaats, records show that during the 

 period of twenty years there is no month throughout the year 

 in which frosts are not liable to occur. However, in general, 

 the interval between killing frosts is usually sufficiently long 

 not to affect the maturity of most of our commonly grown 

 summer crops. It is in seasons when the commencement of 

 rains is late that frosts are apt to be a very limiting factor. 



As with the rainfall, it is found that there is a gradual 

 increase in temperature along any parallel from west to east. 

 This is true in a general way, provided the stations chosen to 

 exemplify this are fair distances apart, since there are limita- 

 tions imposed by local circumstances. 



Almost throughout the whole of South Africa the mean 

 temperature is approximately 62° Fah. However, the mean 

 maximum and the mean minimum temperatures differ widely 

 in the different parts. The mean daily range in temperature 

 for the whole of South Africa is approximately 24.5° Fah. It 

 is interesting to compare these with those occurring in the 

 tropics, e.g., at Colombo, where the daily range is only 11° 

 and the thermometer practically never registers lower than 75° 

 or higher than 86°. 



The peculiar and marked difference between the conditions 

 on the east and west coasts alluded to has been accounted for 

 by the fact that the warm Mozambique current washes the 

 eastern shores in its southerly course, while the colder Benguela 

 current in its northerly course performs an exactly contrary 

 office for the western shores. The first gradually loses its 



