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MR J. M. WORDIE ON THE NATURAL HISTORY OF PACK-ICE 
II.— Early Stages. 
Formation . — In the Weddell Sea, formation of new sea-ice took place both in 
rough water and in smooth ; and the resulting structure differed accordingly. One 
had to distinguish, therefore, between young-ice formed in calm water, and ice 
formed on a ruffled sea. The former condition was found to be much the commoner ; 
the latter was only noticed as a consequence of the very strongest blizzards, when 
the pack was completely broken up and rearranged. At no time during the voyage 
of the Endurance was the open sea seen to freeze over except in a dead calm ; 
though in higher latitudes there should be no reason against a rough open sea 
freezing. The general rule, however, seemed to be for young-ice to form in the 
ever-opening pools and leads among older ice, as the latter offered protection by 
damping down any swell. 
(l) Growth of young -ice in still water was studied very frequently in the leads, 
lanes, and pools which were continually forming at all times of the year. In 1915, 
when in lat. 77° S., young-ice was noticed for the first time on February 6, and a 
week later all leads began to freeze almost as soon as- formed. This went on until 
October, when for new leads to freeze became unusual ; the ship’s position was then 
in lat. 69° SO 7 S. Water-skies were noted as being numerous on October 9 ; and 
on the 11th young-ice freshly formed on a pool had melted. In 1916, owing 
to the N.N.W. drift of the ice-floes on which various camps were situated, observations 
were made in much lower latitudes ; young-ice did not start forming that year 
until the first week of March, and then only in a cold snap, the latitude at the 
time being 64° S. 
The ideal opportunity for observing the first stages of ice-formation was such as 
was found on May 2, 1915. On that date a crack, formed in heavy hummocky 
pack, opened to a lead, and from a distance was seen to be giving off abundant 
frost-smoke. By reason of the crack having formed in heavy pack of composite 
origin, the bounding walls were seldom perpendicular ; occasional tongues of ice 
jutted out into the water at various depths, and by reflecting up the light showed 
the intervening water filled with freely floating small platy crystals of ice about the 
size of a finger-nail. They had not yet arranged themselves or coalesced in any 
way, but seemed to fill the water for a depth of some feet. The water above such 
a jutting ice-tongue was probably chilled to a much greater depth than farther out 
in the lead, being bounded both below and on one side by ice, and above by the cold 
air ; and this might account for the number of shimmering crystals in the water. 
As the crystals became more definite, they rose to the surface, and one could almost 
see them arranging themselves on to the film growing out from the edge of the lead. 
Such a fringe of young-ice was generally referred to as “black-ice” ; the blackness, 
however, was largely due to contrast with the surrounding snow-covered floes. As 
a general rule it had a smooth but slightly damp upper surface formed of platy ice- 
