1886.] illustrating the value of Cape Point as a Warning Station. 21 1 



A great quantity of the electricity contained in these cumulus 

 ^clouds will be dissipated into the upper stratum and the particles of 

 water Avili coalesce and fall as rain. As long as the cloud receives 

 fresh supplies, the cirro-filum will stream off and the rain fall, but 

 as soon as the supply ceases the rain will also cease and the cirro- 

 filum break up into ordinary cirri. As soon as a fresh supply of 

 .moisture is received, more cirro-filum clouds will be formed, in their 

 turn to break up. It is thus we see such varying banks of cirri roll 

 • over us without a single cloud of medium altitude being seen, those 

 generating clouds being far below the horizon, but surely advancing 

 towards us. An expert if he but knows the point of the compass 

 from which the threads seem to radiate and the direction they are 

 travelling from, can tell exactly what the directions of both currents 

 ;are. 



Cirro-filum is a sure forerunner of rain. For the last two years 

 . 1 have seldom known this indication to fail. And where rain did 

 ,Dot follow at Cape Town it was experienced further up-country. 



I intend to introduce as a concluding portion to my paper some 

 -descriptions of one or two good typical winter storms which have 

 visited us this year, with an account of the indications of their 

 .approach. 



The first of these is a double depression, one which came from the 

 north-west, immediately followed by a very severe one from the 

 rsouth-west. The whole disturbance extending from the 11th to 

 the 17th August last. 



On the 11th the only indication of a coming depression was the 

 .thermometer at Cape Point which at 8 a.m. was 3° higher than on 

 the morning before. The general wind was south. On the 12th 

 although the heat was the same, yet the barometer was '09 of an inch 

 'too high, shewing a rapid advance. As the general wind was south, 

 .and that at Cape Point so nth-east, the indications were for a depres- 

 sion from the north or north-west. Next day, the 13th, the heat 

 was 2° higher, while the barometer was '07 of an inch too low at 

 ^Cape Point; the wind blowing a south-east gale. By the low 

 barometer the first depression had passed, and by the high ther- 

 mometer another one was not far off. On the 14th neither barometer 

 .nor thermometer gave any indications, but the prevailing wind was 

 •north-west, while at Cape Point it was north-east ; when the exact / 



• changes took place of course I cannot say, but the indications were 

 if or an approaching cyclone from the south-west. On the loth the 



