243 



In Petermanirs Geog. Mitth. for 1881 Hoffmann gives a general 

 phenological chart for central Europe showing the acceleration or 

 retardation of the phases of vegetation with respect to Giessen. 



In the Zeitschrift, 1882, Vol. XVII, page 457, Hoffmann gives the 

 results of his study of observations collected by Karl Fritsch, showing 

 the dates of blossoming and ripening of fruits in Europe, as reduced 

 to the latitude and altitude of (xiessen; and, second, the thermal con- 

 stant by Hoft'mann's method from observations at (jiessen for the 

 years 1881 and 1882, as collated in the preceding table. He also 

 shows that the advance of vegetation in the early and very warm 

 spring of 1882 did not materially diminish the sums total of maxi- 

 mum temperatures, the figures for which I have reproduced in the 

 preceding table (p. 240). 



MARIE-DAVY. 



The extensive researches conducted at the observatory of Mont- 

 souris (Paris) are scattered through many annual volumes, from 

 which I have culled sufficient to show the views held by Marie-Davy 

 and his coworkers, wiio distinguish very clearly between thermometry 

 and actinometry, and attempt to determine separately the constant 

 amounts of air temperature and of sunshine which constitute the 

 total molecular energy needed to develop the plant. 



In his Annuaire for 1877 Marie-Davy quotes from Tisserand (1875) 

 and Schuebeler (1862) the results of a series of observations on the 

 culture of grain in Europe. Special praise is given to the records 

 from Norway and to the high state of education among the Norwegian 

 farmers. The durations of the periods from sowing to ripening are 

 as follows : 



For other plants — oats, peas, Ijeans, vetches, etc. — the duration of 

 the vegetating period diminishes in a similar manner as the latitude 

 increases or as the temperature diminishes; therefore we can not 

 assume at once that warmth hastens the ripening, for in this case cold 

 appears to hasten it. I say "' appears," because with the cold comes 

 in another influence, viz, the amount of sunshine. Thus as we go 



