RECORD AND DISCUSSION OF THE DIRECTION AND FORCE OF THE WIND. 



The observations of the direction and force of the wind at Van Eensselaer 

 Harbor, North Greenland, extend over the same period as the other meteorological 

 observations, viz: from September 1st, 1853, to May 1st, 1855. With few excep- 

 tions, these observations were made hourly, and their record available for discus- 

 sion, extends to January 24th, 1855. Those taken after this date will be found 

 recorded (three times a day) in Appendix No. XII. of the second volume of the 

 Narrative of the Expedition. 



No self-registering anemometric instrument was used. The direction of the 

 wind is given uncorrected for magnetic variation of the needle, and was noted in 

 reference to eight principal points of the compass. The course of the wind thus 

 given refers to the lower or surface stratum of the atmosphere. The force of the 

 wind has been estimated as near as possible according to a scale extending from 

 1 to 10; the former number indicating light airs, the latter a hurricane. Zero 

 denotes a calm air. These figures, expressive of the relative force of the wind, are 

 placed in front of the letters indicating the direction, as given by its initial letter, 

 and their relation to the velocity and pressure of the wind is shown in the follow- 

 ing table, used in the United States Coast Survey.^ 



The relation of the tabular numbers of pressure and velocity is according to 

 Smeaton's table, and is practically the same as that following from D. Bernoulli's 

 formula." It may be questioned whether the upper limit (No. 10) of the above 

 table has been reached among the few observations marked 10 in this latitude ; 



» The scale of winds adopted by the Smithsonian Institution does not materially differ from it ; see 

 directions on the blank forms furnished to observers. The Coast Survey table will be found p. 277 of 

 the Superintendent's Annual Report of 1856. 



'^ See art. Meteorology, in Encyclopedia Britannica, 8th edition. 



