Ixii PresidenC s Address. E^ug. 28,. 



METEOROLOGY. 



Our knowledge of the Meteorology of the Colony is steadily in-- 

 creasing : there are now forty-one stations equipped with a full set of 

 instrnnients and 317 rain-gauge stations. The set of thermometers 

 by which a record of the temperature at each hour of the day is 

 obtained is at work in King William's ToAvn, after having beea 

 observed for tw^o years at Van Wyk's Vlei. As the result of its stay 

 at the latter place we now know how the average temperature varies 

 during the twenty -four hours in the various months of the year.. 

 Previously the only place where this was known was at the Obser- 

 vatory ; and as was expected, the temperatuie curve for the Karoo 

 differs considerably from that for the neighbourhood of Cape Town ; 

 for example here the hottest part of the day is about 1.30 p.m., while 

 at Van Wyk's Vlei it is between 3 to 4 p.m. 



The papers read by Mr. Howard and Prof. Guthrie on the reduction 

 of barometer readings to sea-level are of great value and must receive 

 special mention. This reduction, most difficult in a country like 

 South Africa but yet essential for any enquiry into isobaric curves^ 

 has for many years occupied the attention of the distinguished 

 meteorologist. Prof. Loomis, in America ; and it seems as though in. 

 every country the peculiar factor suited to that country must be 

 sought ; I believe that Messrs. Howard and Guthrie are continuing 

 their investigations in this direction. 



A valuable contribution to our knowledge has been recently 

 published by Dr. Karl Dove, viz., the climate of extra-tropical Souths 

 Africa, which is founded to a large extent on the results accumulated 

 and reduced by the Meteorological Commission. He divides the 

 country into a number of belts over which the meteorological con- 

 ditions resemble one another, and for each of these he discusses the 

 variations of temperature, rainfall and humidity of the air throughout 

 the year. 



There is one point in connection with the published results for the 

 humidity to which I should like to draw attention, that is that they 

 all make the amount of dampness too great. For the convenience of 

 the observers, who are all volunteers, the hour of observation is fixed 

 at 8 a.m. local time. Now at this time, even close to the sea, the 

 degree of saturation is greater than for the mean of the day by 4 or 5 

 per cent., and I am sure that this amount is considerably exceeded at 

 inland stations. I was particularly struck with this daring some short 



