62 Rainfall, Natural Drainage^ 



VI. — On Rainfall, Natural Drainage, and Subterranean Water 

 Storage. By Professor D. T. Ansted, M.A., F.R.S., &c. 



Inteoduction. 



Thk natural circulation of water through the agency of the 

 atmosphere and the earth is a subject of extraordinary interest 

 and importance to the agriculturist, and includes perhaps those 

 departments of meteorology and geology which are of greatest 

 use to the practical man. But in its practical application the 

 details of each particular case are so much determined by various 

 local circumstances that the general outline to be met with in 

 scientific books on the subject is not sufficient to satisfy the re- 

 quirements of this class of readers, whilst there is very little 

 special literature in our own language, and scarcely any in the 

 French and German languages, available for their purpose. 



Materials no doubt exist, and have been partially brought 

 together, but observations are still wanting in many departments, 

 and many observations recorded have not been reduced. There 

 is certainly great need of information on the subject, and I will 

 endeavour in the present article to point out, so far as space will 

 allow, both what has been done and what remains to be done.* 

 If I can only hope to do so imperfectly, I may at any rate be 

 able to give useful information, and offer a few practical sugges- 

 tions. 



The subject before us is clearly enough defined by the title. 

 It embraces three distinct but closely allied groups of phenomena, 

 each separately important and interesting, but all mutually 

 dependent, and all combining to form the one great subject of the 

 circulation of water on and within the earth. I will not preface 

 these details with more remarks than are strictly necessary, but 

 confine myself to such a general outline as may serve to connect 

 and illustrate them. 



That matter should exist on the earth in the three forms of 

 solid, liquid, and gaseous or aerial, is a truth so obvious as to be 

 generally admitted without consideration. 



Yet we may well pause to consider that without them there 

 could exist no such forms of life as those we are alone acquainted 

 with, and that without some such association the earth could 

 yield us no satisfactory history of the past, inasmuch as there 

 could be no strata of sandstone, limestone, and clay containing 



* Since this article was commenced, INIr. Glaisher has undertaken to prepare a 

 Report on the subject of British Rainfall, which may be looked for at some early- 

 meeting of the British Association, The subject could not he in better hands, but 

 it will hardly supersede the matter 1 have here brought together, and the Report 

 cannot be available for some time. 



