214 
ment are attained by means of very different sum totals of tempera- 
tures at Poulkova and Brussels. 
But possibly we should have taken the initial point of vegetation 
at some other temperature than 0° C. In order to test this point 
Linsser performs the computations of the sums of temperatures above 
1°, 2°, 3°, 4°, 5°, and 6° C., respectively. His result for-6° C. is as 
follows: 
Group. Brussels. | Poulkova. | Group. Brussels. | Poulkova. 
—= : = ; 
“Ef. XO! | Hf XG 
lites pierre 1 PAW) Goes pales 412 368 
ie ee ee 20 72 | Gis NA Te 995 435 
Sa pee 2 97 lis ie | Pee eee 1,154 788 
4 : 212 224 
None of these successive hypotheses as to the initial temperature 
for vegetation gives a uniform constant any more than does the 
original hypothesis of 0° C. 
A similar study of the sums of the squares demonstrates a similar 
result, so that in general at different places the same phase of develop- 
ment of vegetation requires different mean daily temperatures, dif- 
ferent sums of temperatures, and different sums of the squares of 
temperatures, and there is no zero point that can be adopted that will 
inake these sums equal. 
Linsser then shows that, notwithstanding this result, there still is 
a thermal law concealed in the above figures. For evidently the 
sums for Brussels and Poulkova go on steadily increasing through the 
whole period of vegetation, and at any stage the numbers are very 
nearly in the same proportion, and that proportion is very nearly the 
same as the proportion between the sum total for the year at the two 
places. These annual sums total are for Brussels 3,687, and for St. 
Petersburg 2,253. If now the numbers in the fourth and sixth col- 
umns of the table on page 213 be divided by these annual sums, 
respectively, we obtain the following: 
Ratio of the individual sums to the total annual sums of temperature above 0° C. 
if 
See | Brussels. | Poulkova. eounes Brussels. | Poulkova. 
enue es O07) ioe = O08 sane. 0.30 | 0.36 
Die AL ae 09 | sly [Gece eee 2 .40 40 
Bi aati eee sily | 20 teal Panto 60 | . 65 
Ae thay Ne 21 26 | 
| 
The agreement of these numbers is quite close enough to justify the 
conclusion that’ in two different localities the sums of positive daily 
temperatures for the same phase of vegetation is proportional to the 
