TIDAL OBSERVATIONS 



STATION DATA AND METHODS 



During the Expedition two valuable series of tide observations were secured, one at Cape 

 Flora, Northbrook Island, and the other at Teplitz Bay, Rudolph Island, in Franz Josef Archi- 

 pelago. The tides at Cape Flora were observed from May 21 to August 31, 1904, and at 

 Teplitz Bay from April i to June 3, 1904. 



The gauge at Cape Flora was a plain wooden staff, graduated to feet and tenths, which 

 was wedged in between boulders on the shore (see figure i ) A gale having destroyed the 

 gauge, a new one was set up in the same manner on July 18. 



The gauge at Teplitz Bay (see figure 3) consisted of a heavy wooden framework supporting 

 two pulleys ; a wire, attached at one end to a lead weight of 149 pounds lying on basaltic rock 

 at the bottom of the sea 35 feet below the surface, passed over the two pulleys and terminated 

 in a counterpoise weighing 49 pounds. A light, graduated wooden rod six feet long was 

 attached firmly to the wire to serve as a tide staff. The staff remained stationary, while the 

 framework and ice on which it rested rose and fell with the tide. 



At Cape Flora a bench mark was established on a large basaltic boulder near the shore 

 and marked by a painted cross. The base line A 262.5 feet in figure 2, and angles were 

 measured to the bench mark and different positions of the tide gauge. The bench mark 

 corresponds to a reading of 14.65 feet on first staff and to 14.70 feet on second staff. The 

 series was all reduced to the first tide staff, on which mean sea level corresponds to a reading 

 of 6.076 feet. 



At Teplitz Bay two bench marks were established. Bench Mark i is on a boulder near the 

 shore, and Bench Mark 2 is the top of the capstone of the astronomical brick pier. The latter 

 is 50.99 feet above the former as determined by spirit levels on April 30, 1904. The relation 

 of Bench Mark i to tide staff was not constant, as the frame of the gauge slowly sank into the 

 ice, and was considerably tilted at the close of the observations. The following table shows 

 the results of various levels between tide staff and Bench Mark i, only one station of the instru- 

 ment being necessary. 



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