176 
From the data given by Mangon, Marié-Davy deduces some further 
phenological constants which will be useful, viz, for winter wheat 
in Normandy, the sum of the daily temperatures in the shade, reject- 
ing all below 6° C., from sowing to germination is 85° C.; from ger- 
mination to heading, 555° C.; from heading to maturity, 1,810° C. 
This gives from sowing to heading 640° C., whereas Gasparin, fol- 
lowing his own rule, which takes the sum of all temperatures after 
the date at which the temperature of 5° C. is attained, finds 430° 
for this constant. 
Wheat begins to grow visibly when the mean daily temperature is 
about 6° C. This mean daily temperature is attained on the average 
of many years on the dates given in the second column of the fol- 
lowing table. (See Marié-Davy, 1881 and 1882, p. 184.) The aver- 
age dates of harvest are given in the third column; the interval or 
growing period in the fourth column; the fifth column contains the 
sims of the mean daily temperatures of the air in the shade (after 
the date on which a mean temperature of 6° was attained), the sixth 
column gives the sums of the mean daily temperatures of the 
thermometer in the full sunshine, as determined by Gasparin. The 
close agreement of the two latter numbers is considered by Marié- 
Davy an argument in favor of the idea that temperatures in the sun- 
shine are better than those in the shade as a measure of the influence 
of heat and light on the growth of plants. 
‘ | | Grows | Sum of Sum of 
Place Date of | Wheat | ji pe- | Shade |sunshine 
fe 62:C: harvest. | ee | temper- | temper- 
* | atures. | atures. 
Days. IK Or 
Oranges2s eo Sst ae Ree iol Nig eee eee eee Mar. 1} June 2 M7 1,601 2,468 
Parise: f= Sse stoi ee eh See Oe eee Mar. 15 | Aug. 1 138 1,970 2,433 
Wipsala sss ise. Gh Sano AL a nee She eae wee eee Apr. 20 | Aug. 20 | 122 Es E46 | (eae es 
Ty COM sat la oe ee ee ee een et June 15 | Aug. 27 | 72 675) | =eeeeee 
Balland (see Marié-Davy, 1881, p. 186) has made a perfectly simi- 
lar computation with reference to the ripening of wheat cultivated on 
a large scale at Orleansville, in Algeria, with the following results: 
TSKS seated pe ee ee ee ee ee eee eee 2, 498 
NOU Ole Se SS Pee oo a eee Ey ee ee ee 2, 433 
AN CPAGE: 22) Lie. 8 De ee ee eee 2, 462 
The results of Mangon, Balland, and Gasparin agree so closely: that 
a strong argument seems to be afforded in favor of using the ther- 
mometer exposed to the full sunshine. The differences in their results 
are quite comparable to the differences found by Vilmorin to exist 
between different varieties of the same seed. 
The values of the thermometric constants, as computed by Herve 
Mangon’s method, for other grains cultivated in Normandy are given 
