814 
MR J. M. WORDIE ON THE NATURAL HISTORY OF PACK ICE 
further observation, for other explanations are possible. Chains of pools, in fact, can 
be very easily accounted for by shearing and screwing. 
Effect of Wind on the Drift . — During 1915 a drift indicator was set up on the 
floe about 50 yards from the ship ; it was in no sense a current meter, but was an 
approximation to a drift meter, as it was ultimately possible to deduce the speed of 
the drift from the rapidity or otherwise with which the indicator reacted. It con- 
sisted of iron piping about 9 feet in length set inside a slightly shorter length of ship’s 
rail. The latter was firmly fixed in the floe and was filled with a mixture of salt and' 
petroleum, so that there was very little chance 
of the inner piping becoming fast frozen. A 
vane had been fixed to the lower end of the 
piping, and an arrow-head at the upper end, in 
the same vertical plane as the vane. The arrow 
accordingly always pointed in the direction in 
which the floe was travelling.* Commander 
Worsley made several observations daily, aqd 
at each observation rotated the arrow and the 
vane to 90°; he then waited until they swung 
back, and the time which this took gave him 
a measure of the rate of drift. The result of these observations was to shoAV that 
the floes always travelled with the wind, but slightly to the left. The velocity, 
however, did not depend entirely on the strength of the wind ; it was influenced 
in great measure by the presence or absence of open water in the direction to which 
the ice was being taken, no matter how far off this open water might be. 
M'Clintock and later Nansen have discussed the right-hand deflection in the 
Arctic. One case may be quoted to show the extent of the left - hand component in 
* Of. E. H. Shackleton, Heart cf the Antarctic, vol. ii, p. 413. 
