VEGETABLE PRODUCTIONS OF NORWAY. 247 
everything springs into summer: the trees of one 
accord put on their mantle of green; the wagtail, 
swallow, cuckoo, and corncrake come in rapid suc- 
cession; and by the middle of the month the weather 
begins to be very hot. Last year (1862), for instance, 
at Christiania we could sledge on the fjord till the end 
of April, and by the middle of May the trees were 
covered with their summer foliage ! 
A curious climatic phenomenon may be noticed 
towards the latter part of August. For three or four 
consecutive nights, called ‘iron nights,” sharp frosts 
occur, which frequently do considerable damage to the 
unripe corn; but after this, warm weather again ensues, 
and lasts till the end of September, or even till the 
beginning of October. 
This sudden transition from winter to summer, and 
the absence of the cold blighting winds so prevalent 
in England during the months of March and April, has 
a great and beneficial effect on the vegetation, and it is 
seldom that the currants and gooseberries get cut 
off by early frosts. When once, however, vegetable 
growth commences it is carried on with amazing 
rapidity. My observations have led me to conclude 
that vegetation in the neighbourhood of Christiania, 
lat. 57° 54’ 43", at midsummer, is about a fortnight 
behind that in the midland parts of England. 
As just mentioned, the corn often suffers great 
