— 178 — 



Spruce in the middle and northern parts 



Spruce in the southern part of Germany. 



Probable % Diff. 



±13.5% 



d=I6.9% 



±19.1% 



± 0.9% 



± 0.4% 



± 0.9% 



± 0.2% 



± 1.1% 



± 4.6% 



± 6.8% 



± 2.0% 



± 2.0% 



± 2.8% 



The following diagram (Plate XXIX) show the comparison between the 

 theoretical and the given results. 



From the above table and the plates it will be obviously seen that 

 there are some regular discordances between the curves from the tables 

 and those from the equations. This comes to happen, I think, from the 

 disagreement of the curves from the tables with the given data, of which 

 the tables must be constructed. I have examined the agreement of equa- 



tion: y='ke directly with the given data. From these results, I 



continue to assert the truth of the above equation. To ascertain this 

 formula it is needed to give numerous illustrations, but this is not the 

 object of the paper. 



