In both cases, with calm conditions, the tidal compressions and thinnings occurred alter- 

 nately with amazing regularity and we could count on them in advance. This fact gave me reason to 

 propound the concept of "ice time. " By this is understood the average time interval between the 

 time of upper meridian passage of the moon and the next following compression of ice in the given 

 point of the sea. Thus, the concept of "ice time" is analogous to the concept of "high water luni- 

 tidal interval, " by which is understood the average time interval between meridian passage of the 

 moon and the following high tide. 



Just as the lunitidal interval for every port is determined by observations, and the longer 

 the series of observations the greater the accuracy, so also for determination of ice time appro- 

 priate observations are necessary. In determining the lunitidal interval all cases of wind-caused 

 raising of level must be excluded. Likewise, in determining the ice time, cases of wind compres- 

 sion of ice must be excluded. 



After the ice time is determined for a number of points of the region under investigation we 

 are able to plot the lines of simultaneous flood-tide compression in the given region, or the "ice 

 lines, " in exactly the same way as we plot the cotidal lines--lines of simultaneous high tide or 

 lines of position of the crest of the tidal wave in lunar hours counting from the time the moon 

 passes through the meridian in the given place. 



TABLE 96. INTERVAL BETWEEN FLOOD- TIDE TO 



EBB-TIDE MOVEMENT OF ICE RELATIVE 

 TO CULMINATION OF MOON (MERIDIAN 

 PASSAGE) IN THE LAPTEV SEA 



Date Interval 



25 November 1937 8 h 16 min 



2 December 1937 9 h 17 min 

 9 December 1937 8 h 16 min 



18 December 1937 8 h 14 min 



26 December 1937 7 h 34 min 

 7 January 1938 5 h 50 min 



11 January 1938 7 h 14 min 



15 January 1938 6 h 00 min 



19 January 1938 7 h 13 min 



3 February 1938 6 h 15 min 



7 February 1938 7 h 19 min 



8 February 1938 5 h 14 min 

 14 February 1938 6 h 45 min 

 17 February 1938 6 h 13 min 



Average 7hll min 



In table 96, extracts are given from the table computed by Storozhev from which it may be 

 seen that the change from flood-tide to ebb-tide drift of ice — which corresponds to the thinning of 

 the ice — occurred on the average of 7 hours 11 minutes after the culmination (meridian passage) of 

 the moon. This time interval must be considered as the ice time for the drift region of the ice- 

 breaker Lenin . 



LITERATURE: 54, 77, 126. 



341 



