404 
Transactions of the Boyal Society of South Africa. 
Summary. 
1. The potential gradient due to the normal electrification of the 
atmosphere varies inversely with the altitude, but the observations 
taken do not show any proportionality. 
2. The daily variation in the value of the gradient follows the same 
course in places at high or low altitudes, save in the case of Johannesburg. 
3. The variations at Johannesburg are due to the presence of steam 
and dust from the mines. 
