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 



