PREFACE. 



The following treatise owed its origin, and the first issue of it to a desire 

 which I felt to show that it is quite practicable to prevent, or to moderate 

 inundations at the Cape of Good Hope, such as occasionally occur there, 

 destroying property of great value. For some years I held the appoint- 

 ment of Government Botanist in that Colony, and there saw something of 

 the appearance of these inundations, and the serious consequences following. 

 Of both I have given details in a volume, entitled " Hydrology of South 

 Africa ; or. Details of the former hydrographio condition of the Cape of 

 Good Hope, and of causes of its present aridity, with suggestions of 

 appropriate remedies for this aridity."* And in the preface to the former 

 issue of this treatise, I had occasion to state — " I have before me details of 

 destructive effects of torrents which have occurred since I left the Colony 

 in "the beginning of 1867. Towards the close of that year there occurred 

 one, the damage occasioned by which to roads and to house property 

 at Port Elizabeth alone was estimated at from ^25,000 to £30,000. 

 Within a year thereafter a similar destructive torrent occurred at Natal, 

 in regard to which it was stated that the damage done to public works alone 

 was estimated at £50,000, and the loss to private persons was estimated 

 variously from £50,000 to ^100,000. In the following year, 1869, a torrent 

 in the Western Province occasioned the fall of a railway bridge, which issued 

 in loss of life and loss of property, and personal injuries, for one case alone of 

 which the railway proprietors were prosecuted for damages amounting to 

 £5000. In Beaufort West a deluge of rain washed down the dam, and the 

 next year the town was flooded by the waters of the Gamka ; and the next 

 year, 1871, Victoria West was visited with a similar disaster. Such are 

 the sums and the damages with which we have to deal ia connection with 

 this question, as it aflects the case ; and these are only the most remarkable 

 torrents of the several years referred to. 



" Towards the close of last year, 1874, still more disastrous eflfects were 

 produced by torrential floods. According to the report given by one of the 

 Colonial newspapers, the damages done could not be estimated at much 

 less than £300,000. According to the report given by another, the 

 damage done to public works alone was estimated at £350,000,-^et^Ai 

 millions, seven hundred and fifty thousand francs. And my attention was 

 called anew to the subject. 



* London : C. Eegau Paul & Co. 



