324 ARCTIC VOYAGES. Chap. IX. 



of line could be measured in one of the meridians 

 that are clustered on the Pole, the difficulty of pre- 

 serving it would require the most rigid attention. 



The swinging of a pendulum is perhaps a less 

 accurate method of obtaining the ellipticity of the 

 earth, but it is the operation of a single person, 

 whereas the actual measurement of the meridian 

 line requires several ; and as an increase of gravi- 

 tation takes place from the Equator to the Pole, 

 the latter makes it most desirable that the requisite 

 observations should be made there, or as near to it 

 as possible ; but a ship on an open or icy sea would 

 not answer.* 



The tides at the Pole would be an interesting 

 subject to examine ; but it does not appear that any 

 contrivance on an open sea, or a sea of ice, could 

 be made use of to ascertain the rise and fall. 



Magnetism, atmospherical electricity, and the 

 Aurora Polaris, and all other meteorological obser- 

 vations, would afford scope enough on board ship. 



Should land, however small the portion, be 

 found at or near the Pole, all the various observa- 

 tions would be conducted to a successful issue. 

 It may be presumed that any such land will not 

 be mountainous, as no icebergs are ever sent down 

 from that quarter, these masses having been ascer- 

 tained as products of glaciers on the sides and valleys 

 of high mountains, as in Spitzbergen and Green- 



* The reader is referred to the several portions of this volume for 

 the pendulum observations that have been made and herein given. 



