254 
If we sum up the second, third, and fourth series of figures we 
finally obtain the sum total of the effective radiation received during 
the whole interval from germination to ripening, as given in the 
following table: 
Total radiation received from Rela- 
germination to ripening. tive 
Aver-| value 
Year. age for 
Oct. 22.| _ of 
a. b. C: d. “| actnal 
crop 
STS ee ae So = ee ee a 5,223 | 5,919 | 6,17 6,383 | 5,924) 25.2 
TY Se ae ge et es aye mak See eee 5,342 | 5,344] 5,454] 5,614) 5,438 19.0 
DBs oie te GATOR LY Wal Vales Se dees ee be 5,587 | 5,682 | 5,856 | 5,626] 5,676 | 26.5 
S76 Ss esc he Se Se re ee oe ee | ee 22.5 
1B Uget a wer ee eee Ree yo Bere eae ee ee eee 3,932 | 4,240 | 4,658 | 4,913 | 4,436 15.2 
Sy fee en a AE See ae OU es ae 4,869 | 5,512 | 5,287 | 5,433 | 5,263) 11.1 
TiS yAc NS Saba ER ese ste, neers oe em suet TNE Bese al 5, OL) 44923785. 561 15) 560n | ip s2obn = ase 
S80 eee tere Os Re oe ee ee ee 55910) 65474)" (63206; 653455) 6i1455)Saeeeeee 
PAN OTUE ClOLIGWV CATS hea scree see ne eee ---| 5,102 | 5,288] 5,550) 5,645] 5,396 (ee cee 
The relative value of the wheat crops, as observed at two stations, 
is given in the last column of the preceding table, and the comparison 
of the figures shows that a deficiency of sunshine has a decided effect 
in diminishing the relative value of the crop; but the converse is not 
true, for we may have an excess of sunshine and still get poor crops, 
owing to a deficiency of rain or irrigating water. In fact, the pre- 
ceding study only shows the nature of the influence of the solar 
radiation ; the exact quantitative effect on the amount of the crop must 
vary with the irrigation or rainfall, with the fertilizers applied to 
the soil, and with the peculiarities of the seed. 
As to the rainfall, it was in the preceding cases distributed as shown 
in the following table: 
Rainfall during stages. Total 
sunshine 
take ee rom 
Year of sowing. Germi- _ | Flower-| Ripen- |germina- 
: Heading : A : 
nating. i) sing? ing. tion to 
ripening. 
1LS\ (3 oe Ree eee COUR Ae idlel okt Le easy Let ee 1.19 0.75 0.78 1.72 5, 924 
1 hoy (5 ee ee RE Ree tee ns ye Arye oe See eeepc ed 2.97 1.36 0.99 1.44 5, 676 
2b (2 ee eee, see eeeceneeie  eneeetras ye ie) Cen Se ot et 1.84 1.90 1.65 1.94 5, 263 
From these figures we conclude that the excess of rain in the wheat 
season of 1878-79, which would have been advantageous with a clear 
sky, as in Egypt," was at Paris accompanied by too little sunshine, 
and therefore the crop suffered. For a given quantity of sunshine a 
certain quantity of water is best for the crop; if the sunshine is 
diminished the plant can not use so much water, and that must be 
correspondingly diminished. 
a Or as in the case of irrigation in the arid portions of the United States—C. A. 
a a ee ee ee 
