Fig. 1 represents a normal type of the potential. The weather was clear, with 

 light to moderate winds. 



Fig. 2 represents a case of the potential disturhed by a gale. On Apr. 11, 

 1901, NNW gale prevailed with the following intensities: 13.2 at 11 a. m., 12.G at 

 noon, 12.G at 1 p. m., 11.7 at 2 p. m., 13.0 at 3 p. m., 9.9 at 4 p. m., 11.7 

 at 5 p. m., 7.G at G i\ ra., G.7 at 7 p. m., etc. 



