LETTER III. 



" It has often happened to me to have been occupied by a par- 

 ticular subject of inquiry ; to have accumulated a store of facts con- 

 nected with it ; but to have been able to proceed no further. Then^ 

 after an interval of time, without any addition to my stock of know- 

 ledge, I have found the obscurity and confusion, in which the subject 

 was originally enveloped, to have cleared away ; the facts have 

 seemed all to have settled themselves in their right places, and their 

 mutual relations to have become apparent, although I have not been 

 sensible of having made any distinct effort for that purpose." 



Sir B. C. Brodie, Bart. 



April 18, 1854. 



My Dear Sons, 



1. In my last letter I hope I did not altogether fail 

 of my purpose, which was to shew you, that as trees 

 are commonly regarded, it is impossible to arrive at 

 any satisfactory knowledge either as to their natural 

 size or their natural longevity. And I would fain per- 

 suade myself that you are now prepared cordially to 

 go along with me to the examination of my theory. 



2. Of this theory, I doubt not you still retain a 

 general notion. But before entering on the evidence 

 to be adduced in support of it, or meeting the objec- 

 tions that may be urged against it, it will be desirable 



