1 10 LIGHT SCIENCE FOR LEISURE HOURS. 



plodded steadily onwards, tracking their way over 

 hundreds of miles of ice with the confident expectation 

 of at least attaining to the eighty-fifth parallel, if not 

 to the Pole itself. 



But a most grievous disappointment was in store 

 for them. Parry began to notice that the astronomical 

 observations, by which in favourable weather he esti- 

 mated the amount of their northerly progress, showed 

 a want of correspondence with the actual rate at 

 which they were travelling. At first he could hardly 

 believe that there was not some mistake ; but at 

 length the unpleasant conviction was forced upon him 

 that the whole ice-field over which he and his com- 

 panions had been toiling so painfully was setting 

 steadily southwards before the wind. Each day the 

 extent of this set became greater and greater, until at 

 length they were actually carried as fast towards the 

 south as they could travel northwards. 



Parry deemed it useless to continue the struggle. 

 There were certainly two chances in his favour. It 

 was possible that the north wind might cease to blow, 

 and it was also possible that the limit of the ice might 

 soon be reached, and that his boats might travel easily 

 northward upon the open sea beyond. But he had 

 to consider the exhausted state of his men, and the 

 great additional danger to which they were subjected 

 by the movable nature of the ice-fields. If the ice 

 should break up, or if heavy and long-continued 

 southerly winds should blow, they might have found it 

 very difficult to regain their port of refuge in Spitz- 



