EARTH SHADOWS 



Sound a great conical shadow of Erebus some forty miles 

 wide on to the western mountains. If now an observer 

 were to stand within, or near to the base of this shadow, 

 and looking towards the apex of it westwards, he would 

 see a conic section like that of a slightly inverted cone, 

 seen very obliquely. We noticed subsequently when 

 viewing the earth shadows from our winter quarters 

 at Cape Royds that the two barbs of the broad arrow 

 of the earth shadows were not equally inclined to the 

 vertical, but that their relative angles of slope were 

 directly proportional to the angles of slope of the north 

 and south side respectively of Erebus. It is evident, 

 therefore, that these dark barbs are a shadow projection 

 of the cone of Erebus. The central vertical dark beam 

 figured by Captain Scott has not yet been definitely 

 observed by us. 



" From the above brief notes it will be obvious that 

 Erebus is very interesting geologically on account of 

 its unique fumaroles, its remarkable felspar crystals 

 and rare lavas, as well as on account of its having 

 served as a gigantic tide gauge to record the flood level 

 of the greatest recent glaciation of Antarctica, when the 

 whole of Ross Island was but a nunatak in a gigantic 

 field of ice. From a meteorological point of view, its 

 situation between the belt of polar calms and the 

 South Pole; its isolation from the disturbing influence 

 of large land masses; its great height, which enables 

 it to penetrate the whole system of atmospheric 

 circulation, and, above all, the constant steam cloud 

 at its summit, swinging to and fro like a huge wind 

 vane, combine to make Erebus one of the most interest- 

 ing places on earth to the meteorologist." 



