8 E. Loorms — Contributions to Meteorology. 



phenomena which indicate that the movement of areas of low 

 pressure cannot be fully explained by the theory of a general 

 drift of the atmosphere. We frequently find two neighboring 

 low areas advancing in directions inclined to each other at an 

 angle of 45 degrees, or even a greater angle. In the United 

 States, while a low center is advancing from Florida along the 

 Atlantic coast toward the northeast, another low center may 

 be advancing eastward over the region of the Great Lakes, and 

 the two low centers may coalesce somewhere in the neighbor- 

 hood of Nova Scotia or Newfoundland. It will be seen from 

 the accompanying plate, that the storms which proceed from 

 the Gulf of Mexico and from the neighborhood of the West 

 India Islands, generally advance toward Newfoundland ; and 

 the storms which come from the northwestern part of the 

 United States, also tend toward the same region. Newfound- 

 land becomes thus a point of convergence of storm tracks pro- 

 ceeding from regions quite remote from each other. In the 

 vicinity of Newfoundland, there exists some influence which ap- 

 pears to act as an attractive force upon storm centers. This 

 influence probably results from the great amount of precipita- 

 tion near that island, arising from the proximity of the warm 

 water of the Gulf Stream, to the colder air from the land. The 

 accompanying plate shows other points toward which storm 

 tracks seem to converge, particularly the Asiatic coast near 

 Japan, and this fact probably results from a cause similar to 

 the one just named. If the accompanying plate exhibited the 

 storm tracks of different regions according to the relative fre- 

 quency of their occurrence, other points of convergence of 

 storm tracks would be exhibited. Along these converging 

 storm paths, two storms often travel simultaneously and coalesce 

 in a single storm area. Such a movement appears inconsistent 

 with the drift theory. 



For the convenience of those persons who may wish to inves- 

 tigate cases of this kind for themselves, I present the following 

 list which shows some of the most decided cases in which two 



Examples in which two centers of low pressure approach each other 



and coalesce. 



1873. 



March 



29.1-29.2 



1875. 



Nov. 10.1-10.2 



1879. 



Jan. 



1.3- 2.2 





Oct. 



4.3- 5.1 



1876. 



March 25.3-26.1 





Feb. 



4.1- 4.2 





Oct. 



11.1-11.3 



1877. 



Dec. 29.3-30.1 





Oct. 



16.1-17.1 



1874. 



April 



19.2-19.3 



1878. 



Feb. 14.3-15.1 





Oct. 



28.2-28.3 





April 



25.2-25.3 





March 13.3-14.1 





Nov. 



20.1-20.2 





Aug. 



30.2-31.1 





May 2.1- 2.2 



1880. 



Feb. 



13.1-13.2 





Sept. 



25.1-25.3 





June 18.1-18.2 





March 



7.2- 8.1 



1875. 



Jan. 



22.2-22.3 





Nov. 22.1-22.2 





Oct. 



29.2-29.3 



centers of low pressure in the United States have coalesced. 

 They are taken from the Signal Service Weather Maps for the 



