788 
The Action of Light on Plants . [December, 
air drier, the quantity of rain less, the winters are cold 
and the summers hot. The isothermic line passing through 
the places whose mean temperature is zero, — skirting in 
Norway the chain of mountains and the sea coast from the 
North Cape, embracing also the central part of that country 
between the 6oth and 63rd parallels — begins in Finland at 
the 66th degree of latitude, and rises rapidly to the north, 
forming a curve which encloses the elevated lands of the 
interior between the Gulf of Bothnia and the Ardtic Sea, 
so that not only the countries situated south of that parallel, 
but also those which slope towards the Ardtic Ocean and 
are submitted to the salutary influence of the Gulf Stream, 
have a mean temperature above zero. Of all the countries 
situated in the same latitude as Finland, the Scandinavian 
peninsula alone enjoys a milder climate. European Russia 
is much colder, and the climate of Asiatic Russia still 
severer. The neighbourhood of the sea and the abundance 
of lakes — in the number of which no country in Europe, or 
perhaps in the world, can compare with Finland — cause a 
tolerable quantity of rain to fall, and render the climate 
somewhat humid. 
With regard to the adtion of prolonged solar light on the 
vegetation common to all those countries, Dr. Schiibeler, of 
the University of Christiana, has demonstrated that the 
seed of corn or other plants obtained from the northern 
regions ripens more quickly than that produced in the more 
southern countries. In the regions of the extreme north, 
where grain crops are uncertain in their yield, owing partly 
to the elevation of the land above the level of the sea, the 
seed corn of the north is always used in preference to any 
other. It is not Jess true that the various kinds of grain 
and vegetables cultivated in the northern regions yield 
better and are much richer in carbo-hydrates than the 
varieties cultivated more to the south. The colour, more- 
over, is deeper — a phenomenon which applies also to all 
trees and plants. Foreign botanists visiting Norway, and 
the other countries of the extreme north, in summer, are 
astonished at the fresh dark green of the foliage and the 
bright colours of those flowers which grow both in northern 
and southern climes ; and as this richness of colour in- 
creases regularly with the latitude, trees and plants have at 
first been considered as new varieties. The leaves of trees 
grown in the north are larger even when the seed has been 
brought from more southern countries. M. Schiibeler has 
likewise proved that the aroma of all kinds of plants and 
fruits, both wild and cultivated, increases as the north is 
