1093 



2. Increased accuracy of the material, by collecting all available 

 data concerning the winters in this district and its periphery, with 

 a critical comparison of the data. 



3. Consideration of the data on m i 1 d winters also, since these 

 were not included in Köppen's material. 



So I tried, although restricting myself to the cold season, to obtain 

 for the area mentioned aboxe a survey of the whole course of 

 winter-temperature for a very long interval of time. The data from 

 the earliest centuries are of course defective and very incomplete. 

 A card register and a bibliography were arranged, the latter 

 especially with the purpose to determine as accurately as possil)le for 

 each historical item the area to which it refers. I took much (rouble 

 to use every source of some importance, although some of them were 

 rather inaccessible; so not oidy rare books such as Pit-gham's "ünter- 

 suchungen über das Wahrscheinliche der Wetterkunde", Nkiktkr's 

 "Rigidiores Hiemes", or Billing's "Chronique d'Alsace", have been 

 consulted in the original, but also English sources as Baker and 

 LowK, which happened not to be available on the continent, have 

 been studied in the library of the British Museum. Although the 

 collected material may certaiidy not claim completeness, slill, when 

 comparing it with some recent papers, as Speersciineidkk's '), there 

 appears to be. every reason to consider the result of my compilation 

 as fairly final in its outlines. 



Only in a few cases, when recording the data for more remote 

 times, 1 went back to the original chronicles. Controlling those 

 innumerable witnesses by means of the original sources might some- 

 times have resulted in the elimination of eriors, but these impro- 

 vements in details were out of all proportion to the enormous labour 

 involved, and following this course would have indetinitely post- 

 poned the completion of the investigation. Moreover the compilations 

 of PiLGRAM, Pfafe, Schnurreh, Arago — DE Barral, aud others seem 

 on the whole reliable, and I he dala control and complete each 



The border of the periphery runs from tlie Shetlands over the East of 

 Scotland, follows the Welsh border, runs over Brighton, E. of the Channel Islands 

 over St. Nazaire to St. Sebastian; it contains the N. E. of Spain and the S. of 

 France with the exception of the coastal parts; also the plain of the river Po, 

 and passes over Kiume and Vienna to Gotland, then goes with a bend to the 

 south-west, so that only the S. W. coasts of Sweden and Norway lie within the 

 periphery. 



For the periphery the results of this investigation hold only partially. 



1) G. J. H. Sfebrschnkider. "Om Isforholdelse i Danske Farvande 690- 1860". 

 Publik. Dafisk -Met. Inst. 1915. (On Ice-conditions in the Danish waters from 

 690 to 1860). 



76* 



