16 REPORT OF THE SECRETARY. 



longitude finally adopted for the observatory of Van Rensselaer 

 harbor was 70° 52' 45" west from Greenwich. It may be interesting 

 to remark that the degree of longitude in this high latitude is a little 

 less than twelve nautical miles, (11.88.) 



Besides the astronomical observations at Van Rensselaer Harbor, a 

 number were made on the coast of G-reenland when the expedition was 

 on its way to its winter quarters, and a series for determining latitudes 

 by travelling parties at different points in. the regions explored. 



From the full discussion of the whole series of observations both for 

 latitudes and longitudes a new map which accompanies the paper has 

 been protracted. This map differs from that given in Dr. Kane's nar- 

 rative in shifting the position of the shore line of Kennedy Channel to 

 the southward about nineteen nautical miles. The highest point of the 

 eastern shore line traced on the corrected map is in latitude 80° 56', 

 and that on the western side of the channel 82° 7'. These are the 

 northern limits of the exploration of the G-rinnell expedition. 



The fourth and last series of discussions and results of observations 

 made by Dr. Kane during the second expedition has also been printed, 

 and will form a part of the thirteenth volume of the Smithsonian 

 Contributions. It relates to the tides in the Arctic seas. Occasional 

 observations on the height of. water were taken after passing Smith's 

 straits, but the principal number recorded were made at Van Eens- 

 selaer Harbor. The series at this place commenced in September, 

 1853, and was continued to January, 1855. The observations during 

 this period are very unequal in value, owing mainly to physical diffi- 

 culties. The observations, by means of a sounding line or staff, were 

 subject to irregularities from a slow movement of the vessel, which, 

 though imbedded in the ice a greater part of the year, was not entirely 

 stationary. The observations, by means of a string passing over a 

 pulley and attached to afloat, were also subject to certain irregularities 

 due to an occasional slipping of the rope over the pulley, and another 

 small variation caused by the gradual rising of the deck of the vessel 

 above the level of the water, in consequence of her becoming lighter 

 by the daily consumption of provisions and fuel. 



In discussing these observations it was necessary in the first place to 

 reduce the measurements to the same zero or level of the sea. To 

 effect this, two curve lines were traced on paper, the upper one including 

 the maximum rise of water for each day, and the other the lowest water 

 for the same time. An intermediate line traced equidistant from these 

 curves was then assumed to represent the mean elevation, and this 

 Straightened out was adopted as the axis of the mean level of the sea. 



