AS OBSERVED IN THE WEDDELL SEA. 
825 
fibrous and were in fact simply young-ice. The spotted ice formed in 1914 or earlier 
is often referred to as old-ice ; unlike young-ice, it had experienced high summer 
temperatures. 
The two series in young-ice show how even in five weeks there has been a distinct 
freshening of the ice ; in the case of the salter layer (25 cm. down) the loss in 
chlorine amounts to 25 per cent. Layers less salt have not freshened in the same 
proportion. The curve has become smoother, and it looks on that account as if 
finally the amount of chlorine were going to be equally distributed through the ice, 
except perhaps in the very bottom layers where the ice is but newly formed. 
The series in old-ice shows a freshening of the same order, but much more 
advanced. The very high chlorine percentage in the sample near the surface seems 
out of place : it is explained, however, by the upper surface of the ice at this point 
having been below water level, owing to its heavy load of snow ; for in such cases 
salt water always seeped in laterally from the nearest crack and caused the upper 
layers of old spotted ice like this to appear even salter than the young fibrous 
variety. The fact remains, however, that spotted ice as a rule is fresher than 
fibrous ice. 
To summarise : — Young-ice had two possible lines of development open to it : 
either it remained floating in water or was hummocked. In both cases its structure 
became spotted instead of fibrous ; in the case of hummocked ice, it also became 
translucent in appearance. The saltness was appreciably lessened in ice afloat, but, 
if hummocked, the ice became fresh enough even for drinking purposes. That 
a little chlorine, however, was still present even then was proved by titration with 
silver nitrate. 
V. — Decay. 
To the rule that Arctic and Antarctic pack are much the same there appears 
to be one noteworthy exception. In the matter of decay, sea-ice in the Antarctic, 
by all accounts, behaves very differently from that in the Arctic. It was a very 
rare thing, for instance, to see bare ice in the Weddell Sea, and when it did occur 
it was owing to the ice having formed late in spring and never having had an 
opportunity of getting covered by much snow. In no case was a pool of fresh 
water due to natural causes seen on the ice ; salt pools certainly were seen, but 
they were all due to seepage of water into depressions caused by the weight of 
pressure ridges. Fresh-water pools, formed on camp sites owing to the amount 
of soot lying around on the snow, may be set aside as unnatural. Under excep- 
tional conditions, however, fresh pools do occur in the Antarctic ; Nordenskjold 
mentions having found them on the ice near Snow Hill Island, but gives no 
details ; and they also occur in the Ross Sea in places where there is a good 
deal of dust scattered about over the ice. 
In the Arctic affairs are very different, and melting of the snow to form 
fresh-water pools and lakes is extremely common, particularly in the American 
