92 
B. If the number of rain-days is 100 percent above 
the average then the tree growth is 40.6 + 6.5 percent 
above the average. 
As for the influence of winter-rains or snow Î find in 
Treves that the influence is vanishing. 
On the other hand the comparison of the wood growth 
of our trees from Coblentz, Westerwald, Taunus and 
Vogelsberg (see fig. IV) leads to a very small influence 
of spring and summer rain, whereas there is a decided 
favorable influence of winter-rain (or snow), the result 
being: 
If at Boppard and Frankfort, the rain and snow in 
winter is 100 percent above the average, the tree growth 
in the following summer will be above the average (in 
the forests mentioned) 
13" 5" percent. 
III. More accurately, Ï find from the Main and Ems 
curves: Epoch of minimum 1745.6, period 12.36 years. 
In other trees there is also the indication of a period of 
16.54 years, with the epoch 1751.7 which may really 
have to be subdivided in two periods of 8.27 years. It 
15 toMbe notedithat 1241Mistexactly —"/72016/540) 
The theoretical times of minimum corresponding to the 
12.43 vyear-period are: 
1659.1 1708.5 
m* 207 
83.8 3352 
96.2 45/0 
1) This fact might perhaps suggest the feasibility of the development 
of the wood-growth in a Fourier series. 
