74 
by the number of hours of sunshine, only rejecting the useless night- 
time, Just as one would reject the useless low temperature. In the 
absence of sunshine records he uses the number of hours between 
sunrise and sunset, or the duration of diffuse sunshine, and obtains 
for spring wheat and barley the data given in the accompanying 
table, where the last column may be said to give “sunshine hour 
degrees.” 
Sunshine hour degrees. 
Sunshine 
. nour 
Plant and locality. Datitude Desible anheee: jpebrees ; 
: sunshine. | perature. | pine Soe 
shine). 
Spring wheat: . Dips hl (Of 
PNISR Ole tee eee ee bea a ns ee eee 48 30 1 996 15.0 29 900 
Christiania ee. cae oe era eee ee eee 59 9 1 795 15.4 27 643 
Halsnos See eet: hace ck ee es ek ee eee ee eee | 59 47 2 187 13.0 28 431 
BOGOF ee oe ee ee fees ore Cee es aera ee 67 17 2 376 11.3 26 848 
S Grr) Ce ae ee ee eee ee eee ee ee 68 46 2 472 10.9 26 244 
Skibotten?sceesas sce oes eee ee meee ee eee 69 28 2 486 10.7 26 600 
Barley: 
PAN SS. COlae see eee io hee a ee ern ee 48 30 1 416 19.0 26 900 
Christiania sete) Se ee ee ee ea ae 59 9 1 620 15.5 25 125 
IH BISNOs: - vee see eee ek eae eis a ot AE ee 59 47° 2 035 Tey 23 809 
BOG Oba 22 seen eee Sener ee ee 67 17 2 138 11.0 23 000 
Skibotten ___.__- Speco ere 2h Sena oe hoe me 69 28 2 138 10.7 23 000 
1D Yo eenewe ees 2A Se eRe AA Sanh eye ee eee ae 69 28 1 824 12.7 22 876 
We see that the sunshine hour degrees diminish as the latitude in- 
creases. This diminution ought to be rather more rapid in propor- 
tion as the actual state of the cloudy atmosphere approaches the theo- 
retical state of absolute clear sky. 
Thus Halsno and Bodo, localities which have very nearly the same 
soil, the same altitude, the same orientation, the same distance from 
the sea, but which are more or less under the influence of the aqueous 
vapor coming from the Gulf Stream, have a cloudiness during the 
evolution of wheat of 5.6 and 7; during that of oats, 5.4 and 7; where 
0 represents perfect freedom from clouds and 10 completely covered. 
If records of cloudiness could have been used, the numbers in the 
last column would have been computed like those in the following 
table: 
[Possible] Gioudi-| Gear ery [dally | _Sun- 
ait, || essa 4 ree tempera-| shine. 
: ture. 
| 
Spring wheat: Hours. | Tenths. | Per cent.| Hours. | Degrees.| Hours. 
Haleniomee od f0: os see ee 2,187 5.6 | 44 982| 13.0] 12,506 
(IBOGOE a ers ecb soos eee 2,376 7.0 | 30 713 11.3 7,865 
Barley: 
Ep lsno ese mem hi ee aS Racers Witney 46 936 11.7] 10,951 
Bodo? tay A Pils ee kn | 2,188 | 7.0 30 641 11.0 7,051 
