Be 
the appencix. Wind data were collected from the U. S. Weather Bureau at the 
stations and forwarded to Mrs. Cotell. 
Drift of the ice was also studied by measuring currents beneath the 
ice, Gurley current meters (bucket-wheel type) were used and proved only 
partially satisfactory. Their calibration depends on the condition of the 
bearing and the commutator box must be fille? with oil or glycerine to prevent 
shortins by salt water. At Station Alpha currents were read at various 
depths in an attemot to find the velocity cradient beneath the ice and the 
"roughness factor" of the ice. A biplane drag meter was also read at 
various depths to describe the Ekman circle pattern beneath the ice. During 
the summer of 1958 at Alpha, two Gurley meters were read simultaneously at 
different depths and then interchanged to eliminate instrument calibration 
differences. A biplane drag meter was maintained at a large depth. Currents 
were read twice daily during this period in an intensive effort to delineate 
current patterns beneath a wind driven ice floe. A Roberts radio current 
meter was to be used for the continuous recording of current, but proved 
too insensitive for the small magnitudes of current involved. Only at one 
instance tas the drift rapid enoveh to permit its use at Alpha. 
A meter designed by Dr. Thorndike to measure bottom currents was 
also given trial at both Aloha an? Charlie; difficulties of operation prevented 
successful measurements at either station. 
In addition measurements of absolute velocity of the floe over 
the ocean bottom were made with two different techniques. At Station Charlie, 
the PDR provided opportunity to make drift measurements by calculations from 
the "highlights" recorded on the fathocrains. This method involves a simple 
calculation using the hyperbolic reflection from a "highlight." The method 
was first developed at Lamont to measure the absolute speed of a ship over 
the bottom. The second method involves dropping a charge on the bottom 
