72 DISCUSSIONS IN CLIMATOLOGY. 



70° it will occupy 4 square feet, and at latitude 60° the 

 space covered will be 6 square feet. Then, if the layer 

 was 1 foot thick at latitude 85°, it would be only 6 

 inches thick at latitude 80°, 3 inches thick at latitude 

 70°, and 2 inches at latitude 60°. Had the square 

 foot of ice come from latitude 89° it would occupy 30 

 square feet by the time it reached latitude 60°, and 

 its thickness would be reduced to -£$ of a foot, or § of 

 an inch. 



Now, the lower the layer the older it is, and the 

 greater the distance which it has travelled. A layer 

 near the bottom may have been travelling from the 

 Pole for the past 10,000 or 15,000 years, whereas a 

 layer near the top may perhaps not be 20 years old, 

 and may not have travelled the distance of a mile. 

 The ice at the bottom of a berg may have come from 

 near the Pole, whereas the ice at the top may not have 

 travelled 100 yards. 



There is still another consideration which must be 

 taken into account. It is this : the icebergs all seem 

 to bear the mark of their original structure, and the 

 horizontal stratifications appear also never to have 

 been materially altered in their passage from the 

 interior. This fact seems to have struck Sir Wyville 

 forcibly. "I never saw," he says, "a single instance 

 of deviation from the horizontal and symmetrical 

 stratification which could in any way be referred to 

 original structure, which could not, in fact, be at once 

 accounted for by changes which we had an opportunity 

 of observing taking place in the icebergs. There was 

 not, so far as we could see, in any iceberg the slightest 

 trace of structure stamped upon the ice in passing down 

 a valley, or during its passage over voches moutonnees 

 or any other form of uneven land. The only structure, 

 except the parallel stratifications, which we ever 



