214 



merit are attained by means of very ditJ'erent sum totals of tempera- 

 tures at Poulkoya and Brussels. 



But possibly we should have taken the initial i^oint 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 : 



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 

 make 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 iiidiridiKil smnn to the total annual ftunis of tonijeratiire ahore 0° C. 



,The agreement of these numbers is quite close enough to justify the 

 conclusion that in two different localities the sums of i)OsitiA'e daily 

 temperatures for the same phase of vegetation is proportional to the 



