658 TIDES AND CURRENTS. 



p. 141), after a manner similar to, but somewhat more elaborate 

 than that since adopted by Captain Koldewey in East Greenland, 

 and described, p. 664, he says (p. 163):— "Nov. 28. The 

 *' increased thickness of the ice, and consequent gradual rise of 

 " the ship, prevents the tide-gauge from acting correctly, unless 

 *' indeed the entire frozen surface does not admit the due flow of 

 " tide. The difficulty, and incessant labour also, of breaking 

 " away the constantly-forming ice, is too much for the men ; 1 

 " have therefore put it out of gear until spring." 



Also, page 155 ; — " The gale of November 9th came on with 

 *' the thermometer at 20° ; on the 10th the temperature ranged 

 " from 0° to 9°, rising according to the strength of the wind» 

 " The tide-gauge rose one foot above its scale, and I have reason 

 " to believe that some movement of ice unperceived by us shook 

 " the observatory. A heavy snow-bank formed on our port side ; 

 *' water flowed above the ice." 



The Amount of Rise of the Tide. — (II. p. 181.) 



" The rise and fall of the tide is apparent, not only on the tide- 

 pole, but also on the ice, proving that until the floe becomes 

 entirely free from the shore it does not rise and fall to the extent 

 to which the water indicates it should. Thus, in addition to the 

 rise and fall, as exhibited by the true index (the tide gauge 

 secured to the bottom), we notice a rise and fall between shelf 

 cakes of ice deposited at high and low water, a distance of 

 18 inches, fully proving a resistance in rising due to floatation if 

 free. This is specially evident at the in-shore cracks, where the 

 communication is impeded at high water by thin sludgy ice and 

 water." 



On May 14, 1854, strong tidal action was observed, and experi- 

 ments were made by inserting a tide-pole through the fire-hole. 

 The depth was 21 feet 8 inches amidships, and the tide fell one 

 foot within the hour. 



(Vol. II. p. 203.) 



June 25. — "We have noticed that the weather here is more 

 " influenced at the actual moments of the moon's quartering than 

 " at the spring tides, which is opposed to my experience in other 

 " parts of the world. To-day, however, the moon changed at noon, 

 " but the wind, which has prevailed strong, still continues in heavy 

 " gusts ; about 8 p.m. it abated, and at midnight ceased. But the 

 " tide does not appear to coincide to-day with its natural move- 

 " ments, not rising at noon by 6 feet to its natural height, at mid- 

 " night it flowed 6 feet above." 



Some interesting and important facts are recorded by Sir 

 Edward Belcher (I. p. 146) on the production of raised terraces 

 or beaches by the ice being driven up the shore by the tides, 

 and on the formation of fissures in the ice along the line of 

 coast. 



