igo2] ALONG THE GREAT BARRIER 127 



and it is therefore of interest to note the entry made in my 

 diary on this occasion : 



' Over the barrier and to the S.W. could be seen some 

 small or apparently small hills, showing bare rock patches, but 

 nothing could be seen of the Parry Mountains, and judging by 

 our position two days ago we seem to have been viewing the 

 hills which form or are close to the limits of McMurdo Bay. 

 . . . The southern slope of Erebus can be distinctly seen. . . . 

 There seems every probability of getting over this slope on to 

 the ice-plain if we winter west.' 



Already there was a strong case against the Parry Moun- 

 tains, and later we knew with absolute certainty that they did 

 not exist ; it is difficult to understand what can have led such 

 a cautious and trustworthy observer as Ross to make such an 

 error. I am inclined to think that in exaggerating the height 

 of the barrier in this region, he was led to suppose that any- 

 thing seen over it at a distance must necessarily be of very 

 great altitude ; but, whatever the cause, the fact shows again 

 how deceptive appearances may be and how easily errors may 

 arise. In fact, as I have said before, one cannot always afford 

 to trust the evidence of one's own eyes. 



On steaming along the barrier, we soon found that Ross 

 had exaggerated not only its height, but its uniformity. This 

 was perhaps natural, as in a sailing ship he dared not approach 

 too closely, and often had to estimate the height when at a 

 great distance ; and the want of uniformity can only be deter- 

 mined by close measurement. It can be readily imagined that 

 even if the height changes from 70 to 240 feet in ten miles, the 

 change is so gradual that it cannot be detected by the eye at a 

 distance, as the higher part will only appear to be closer. 

 The only way in which the inequality can be detected is to 

 follow the wall closely, when the change of height must be 

 obvious. Ross had to judge his barrier from the very few 

 places in which he was able to approach it closely. 



Though we started with a long stretch of barrier not more 

 than 70 feet high, by the evening of the 23rd it had risen to 

 240 feet. During the night the wind came off the barrier, and 



