Tree-growth and meteorological factors 
by 
J. C. KAPTEYN. 
Preface. The investigation contained in what follows 
has been made over 30 years ago. Its evident incom- 
pleteness has, up to the present, always withheld me from 
publishing my results in any of the scientific Journals. 
The only publicity given to them was that in some lec- 
tures held at various times before different audiences: in 
Groningen Febr. 1889, November or December 1900 and 
Febr. 1909; in Leeuwarden Jan. 1901, in Pasadena (Cali- 
fornia) in December 1908. The last lecture was printed 
in extenso in “the Pasadena Star“ of 19 Dec. 1908. It 
is the reproduction of this lecture which [ now venture 
to lay before the scientific public. With the exception 
of a couple of trifling changes I have adhered to the text 
of “the Star“, but have now added at the end a few 
notes with numerical data, which cannot well be given 
in a popular lecture. 
Ï do not, I think, overestimate the value of the results 
obtained, If I did, I would have published sooner. But 
Ï haven often thought that there might be in them matter 
for stimulating others to undertake this work in a more 
thorough way. Several botanists have confirmed me in 
this view. Still I could not well overcome my reluctance 
till, in June 1909, Prof. H. E. Douglas published a similar 
investigation in the Monthly Weather review. I then 
resolved to publish what I had, in some form or other, 
in the hope that my contribution might help that of Prof. 
Douglas in calling forth more fundamental work from 
