230 Transactions of the South African Philosophical Society. 



9. The percentage of cloud. 



10. The mean rainfall on the roof of the office of the Port Captain, 

 for the 24 hours ending 8 a.m. of the opposite date. 



11. The greatest fall in one day. 



12. The number of times it has rained in 21 years on any given 

 date. 



One important point to be specially noted in these Tables is the 

 spell of low pressure during the middle of July, and the following low 

 maximum temperatures : the lowest mean maximum (and also the 

 coldest day of the year) falling, just as it probably does everywhere 

 else in South Africa, on July 17th.- ; ' 



* The lowest value of mean daily maximum temperature — i.e., 64° — appears 

 opposite July 18th, and belongs, as explained in the text, to the 24 hours 

 ending 8 a.m., July 18th. The hottest day at Greenwich is July 15th. 



