243 
In Petermann’s 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 Giessen; and, second, the thermal con- 
stant by Hoffmann’s method from observations at Giessen 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). 
MARIB-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 Marié-Davy 
and his coworkers, who 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 Marié-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: 
| Mean Sowing to ripening. 
Locality. | fade. Reese Spring | Spring |,. Ours 
| ture. wheat. rye. ley. 
) eee aie CKO Days. Days. Days. 
Reigns) eee alae a Se eee Sanne eee ee | 59.47 6.3 133 139 17 
TEYOYO Oy, Ga he a ee eee Rae ee a oe SR 67.17 | 3.6 121 118 102 
Sins eee ee a ee | 68.46 2.9 115 116 98 
Slcibat tena saeeae ee ene hao! Mie 2 ose | 69.28 2.3 114 113 93 
LNW SARE Se SS eo ee 36745) |Reeeen ease 142 Vos Saal oe ee 
Paris) (Homilleuse) 22 2sss252---42--os=-5---e 2s 2= ) P4850 eu Ses. cede 189) |p eee es soe 
| | 
For other plants—oats, peas, beans, vetches, ete.—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 
