Lake Kiwu and its Islands 89 



question. Our visit to the islands of Lake Kiwu was a matter 

 of great importance because they lie exactly on the boundary 

 line between the two great divisions of the continent, so entirely 

 different in character, the w^estern forest zone and the eastern 

 steppe zone. 



For these reasons, therefore. Lake Kiwu marked an exceed- 

 ingly important point in our programme, and almost immediately 

 after our arrival at Kissenji we started making excursions on 

 the lake in our little folding boats. We seized the earliest 

 opportunity to experiment with dynamite for fishing purposes. 

 Although in a general way such a method of fishing is to be 

 condemned, it may strongly be recommended for purely scientific 

 purposes. No other method, whether angling, net-, or basket- 

 fishing, can give such satisfactory results. Just the factor which 

 renders this method " taboo " for professional fishermen — namely, 

 the killing of young, insufficiently developed fish — makes it of 

 the greatest value to the zoologist, for in this very way he 

 learns to distinguish the younger forms of species from those 

 fully developed, from which they often differ considerably in 

 colour and shape. Dynamite, too, is most serviceable in bringing 

 those fish to the surface which maintain a hidden existence at 

 the bottom, amongst stones and plants, and thereby elude 

 ordinary fishing methods. The quantity of fish captured varies 

 according to the amount of blasting material employed and the 

 plenitude, or otherwise, of fish life in the waters worked, yet it 

 always falls short of an average catch with the net. 



I will not attempt to deny that my first experiment with 

 dynamite caused me a certain degree of uneasiness. Weiss was 

 the only one of us who had had any experience, and that he 

 had almost forgotten. I selected with great care a fuse of 

 ample length, about 60 centimetres, which had to be attached 

 to a bomb weighing some 50 grammes ; so that, whatever hap- 

 pened, I could get well away from the sphere of action before 

 the explosion occurred. Accompanied by my "boy," Ali ben 

 Mahsud, w^ho could manage his oars passably well, I got into 



our little boat and made for the mouth of the Sebeja, which 

 M 



