300 Mr Petcrmann's Notes on the Distribution of 



especially reindeer of the best description, is greatly inferior 

 to north-eastern Siberia in that respect. 



Having now completed this circumpolar view of the dis- 

 tribution of animals, its causes remain to be considered. 



The development of vegetable and animal life in the Arctic 

 regions chiefly depends on the warmth of two or three, or 

 even one summer month ; and it may be in general assumed 

 that where the summer warmth is the highest, there plants 

 and animals will be found in greater number and bulk than 

 in other regions where the temperature is lower. This as- 

 sumption is found to be correct as far as actual observations 

 have been extended. The distribution of temperature in the 

 Arctic regions and its causes I have elsewhere* discussed ; 

 in this place the summer temperature only requires to be 

 considered. To afford, however, the elements of a complete 

 view of the distribution of temperature within the frigid zone, 

 I have collected the observations made at various points, in- 

 cluding some interesting stations not strictly belonging to 

 the Arctic regions : these results are given in the Table (pp. 

 306, 307) and enumerated with respect to latitude. 



According to Sir John Richardson, terrestrial animalsare 

 abundant in the polar regions for two short summer months 

 only. Birds fly to the north to perform the functions of incu- 

 bation and rearing their young, which done, old and young, 

 with the exception of some scattered flocks of dovekies, 

 desert their breeding-places, and with the frost wing their 

 way southwards. Reindeer, musk-oxen, and the beasts of 

 prey which follow in their train, do not quit the continent 

 to visit the Polar islands until the thaw has made some pro- 

 gress in thinning the snowy covering of the pastures, and 

 they return towards the woodlands again as soon as the sea 

 is fast, or sooner, if the straits which separate their summer 

 haunts from the main are narrow enough for them to swim 

 across. The temperature of the month of July, which cor- 

 responds with the summit of the summer, appears to be a 

 pretty sure index of the occurrence or abundance of animals 

 in those regions. The following table exhibits the places of 



* See Petcrmann's " Search for Franklin/' 1852. 



