CHAPTEE VI. 



On the Gorrespoxdence between the Distribdtiox of the Rainfall 

 AND OF. Forests. 



As the student of Anatomy takes up now a muscle, now a nerve, now 

 an artery, and now a vein, and traces it by careful dissection from all 

 integuments and other structures with which it may be united, giving 

 to it for the time his undivided attention, and leaving for subsequent 

 consideration the connections and relations in which each stands to 

 each and each stand to all, so would I pass from the consideration of 

 one subject to the consideration of another, treating each as for the 

 time the one subject with which we have to do, and leaving for sub- 

 sequent consideration the various facts evolved in their combined 

 connections and relations. 



It has been alleged that the distribution of forests corresponds to 

 some extent with the distribution of the rainfall. And this raises 

 the questions. Which is cause and which is effect ? or are they both 

 consequences of a common cause? and in either case to what extent 

 may they be legitimately regarded as cause and effect ? 



In Scottish courts of justice it is customary for the public prose- 

 cutor to lead evidence and then to state his case as founded on this, 

 while in English courts he states his case and then leads evidence to 

 establish it. I do not admit that I have got a case to establish ; but 

 I shall state what my belief is, adduce observations in illustration of 

 different particulars, and then state what I consider to have been 

 proved. 



It appears to me that observations made show in many pases a 

 general correspondence between the distribution of the two — that in 

 many cases the distribution of the rainfall has been determined in a 

 great measure by the geographical position and by the contour of the 

 country, and that this distribution of the rainfall may have determined 

 the distribution of the forests — but that the forests once established 

 may have exei-cised an important influence in further modifying the 

 distribution of the rainfall in time and in space. 



