219 



\\\c suiTs :iltiui(l( 

 I able." 



iiiiinislios. This Linssoi- sliows 



(Ik 



Maximum dura- Altitude of sun at ; Relative quantity of heat re- 

 tion of aunshin*. noon. i ceived by the ground in 1 



day under an atmosphere 



St Pe- whose transparency is 0.70. 



i(lat^4&.4 I (lat (i„o |^ia,^*»-* , (lat.()0° 



N.). 



N.). 



N.). 



j Hours. I Hours. 



January 1(! 9.0 j li.S 



February ir. 10.3 | i».^ 



Marchlti 11.9 j 11.8 



Apriliri 13.5 U.5 



May 16 14.8 17.2 



.Timelo 15.6 18.8 



Julyl6 15.3 18.1 



Augustl6... U.l 15.6 



Septemberl5 -.. 12.6 13.0 



October 16 10.9, 10.;> 



November 15 9.5 7.6 



December 16 8.7 1 6.0 



Dcfjrce.s. 

 2:^.7 

 31.5 

 42.8 

 54.3 



67.8 

 66.0 



58.4 

 47.7 

 35.8 

 26.2 

 21.3 



Degrees. 

 9.0 



49.1 

 53.4 

 .51.5 

 43.9 



m.2 



21.2 

 11.6 

 6.7 



Lat. 



60° N. 



570 

 .525 



:Rt5 



230 

 90 

 20 

 2 



Lat. 



70° N. 



In reference to the first part of this table Linsser remarks that 

 the intensity of the light of the sun varies as the sine of the aiii>iilar 

 altitude of the sun, so that from the maximum altitude on any day 

 Ave get an approximate idea of the influence of sunshine; and Ave see 

 also that the fartiier north we go the longer duration of the sunshine 

 is partly counterb;Uanced bv the diminishing intensity of its 

 influence.'' 



I^insser remarks that the theory of compensation between duration 

 of the day and intensity of sunshine may also be tested by considering 

 the eifect of ascending a mountain, wdiere there is no increase of dura- 

 tion but a great increase in the intensity, of sunshine. If the rapid 

 development of the plants on the mountains is due to the increase in 

 the intensity of the light, then how can the diminution of intensity 

 in northern regions bring about the rapid development that is demon- 

 strated in the experiments of Von Baer and Schuebeler and Ruprecht 

 which are quoted and analyzed in the following paragraphs? 



o To which I have added three columns of relative intensity of the total heat 

 received in twenty-four hours on each date. a>; interpolated from .Vnjiofs tables, 

 for a coefficient of transparency equal to 0.70. — C. A. 



'' The exact figures that yive the relative sum total of the direct sunshine 

 and the diffuse daylight for various latitudes and solar altitudes for clear and 

 cloudless days have been published l)y Marie Davy. Angot. Wiener, and others. 

 The fi.irnres that I have given in the last jiart of the al)ove tables from .Vngot 

 show still more clearly to what e,\tent the effect of sunshine diminishes as we 

 approach the pole, but how surprisingly powerful are the consecutive twenty- 

 four hoiu's of sunshine on .Tune 1.^ within the Arctic Circle. — C. A. 



