RECORD AND REDUCTION OF THE TIDES. 5 



The note of February 3d, 1854, is very instructive in regard to the effect of the 

 tides on the ice floe, viz: "The enormous elevation of the land ice by the tides 

 has raised a barrier of broken tables seventy-two feet wide and twenty feet high 

 between the brig and islands. This action has caused a recession of the main 

 floe ; our vessel has changed her position twenty feet within the last two spring 

 tides, and the hawser connected with Butler Island parted with the strain." The 

 cutwater of the brig was then 280 feet from the margin of the ice. (Note of 

 February 4th.) 



The mean of all the soundings taken during the fourth series is very nearly 

 fifteen feet, hence the constant index error, to refer the observations to the level 

 previously adopted, is eight feet, which correction was applied, converting at the 

 same time the record of fathoms into feet. 



The following tidal record extends, therefore, over about nine and a half luna- 

 tions between October 10, 1853, and October 22, 1854, during which interval the 

 time and height of nearly five hundred high and as many low waters were secured. 



Record of the Observations of the Tides at Van Rensselaer Harbor, North Greenland, 



in 1853, 1854, and 1855. 



Position of the Winter Quarters, 

 Latitude 78° 37' north, and longitude 70° 53', or 4" 43"'.5 west of Greenwich.' 



The first column for each day is copied from the original log-book, the second 

 column contains the reduction to the adopted zero of scale found graphically as 

 explained, and the third column contains the observations referred to the same 

 mean level. 



' See my discussion of the astronomical observations of the expedition in vol. XII of the Smilh- 

 6onian Contributions to Knowledge, 1860. 



