A GEVSER IX SOL'TH AFRICA. 24I 



spring can be stopped until the obstacle is removed ; it has not the power 

 to blow a stick out. of the hole, or a stone off the aperture. No doubt 

 the surrounding springs act as a safety valve in these cases. The 

 water has a slightly pungent smell, which seems to he accentuated in 

 the mud over which the water runs. The mud when drv has a whitcy- 

 brown appearance. 



No trees grow within about a hundred yards of the geyser, on the 

 ground which appears to have been impregnated at one time or another 

 v.ith its discharges ; onlv a little rank grass flourishes on this part. 



From this description it appears that the Fulunka Geyser is 

 not an intermittent but a continuously working- geyser. 



The quantity of water which was placed at my disposal was- 

 very small and I could only determine a few of the mineral con- 

 stituents. 



The waters of the geyser springs of Iceland have be#n 

 analysed by Bunsen, Sandberger, Damour, Bickell, and many 

 others. The most remarkable feature in the chemical composi- 

 tion of the mineral ingredients of the water of all gevser springs 

 is the large proportion of Silica, of which the greater portion is 

 mostly deposited as " sinter " in the vicinity of the springs. 

 Whereas the water of surface springs or ordinary deep-seated 

 springs rarelv contains as much as one grain of Silica per gallon 

 the wa-ters of the Iceland springs contain a very large amount of 

 Silica : the Great Geyser 35 grains of Silica per gallon, the 

 Badhstofa Spring 18 grains, the Scribla Spring 11 grains. The 

 other mineral ingredients of the water of the geysers are not of 

 any special interest. But recently it has been observed that many 

 of the hot springs and of the geysers are strongly radio-active. 



The small quantity of water at my disposal was found tO' 



contain : — 



Silica ^3-65 grains per gallon 



Alumina and Oxide of Iron ... 2.63 ,, ,, 



Magnesia .65 ,, ,, 



Lime 1.50 ,, ,, 



Chlorine 2. 11 ,, ,, 



The examination of the water for radio-activity must be made 



at the spring, since the emanation due to Radium as well as to 



Thorium rapidly escapes from the water. 



There is no doubt that this Interesting and Important subject 

 will receive due attention as the development of Rhodesia pro- 

 ceeds and reaches those regions In which the Fulunka Geyser 

 occurs. 



DARWINISM AND HUMAN LIFE. -Under this title 

 the South African Lectures for 1909, by Prof. J. Arthur Thomson, 

 have just been published by Andrew Melrose, London. In the 

 course of a review of the book in a recent issue of Nature, excep- 

 tion Is taken to Prof. Thomson's treatment of Darwin's term, 

 the "struggle for life." It is held that confusion is caused by 

 enlarging the conception so as to make it include resistance to 

 adverse external conditions, or the strife between carnivora and 

 their prey. 



