NO. 



4 TEMPERATURE VARIATIONS IN THE NORTH ATLANTIC 235 



mum in the temperature amplitude, although there is some indica- 

 tion of it in the curve IV for the interior states. This curve shows 

 besides the halving of the eleven-year sun spot period with a mini- 

 mum in the neighborhood of the sun spot minimum (see in this con- 

 nection the years 1891 and 1902) and a minimum in the neighborhood 

 of the sun spot maximum (compare the years 1884 and 1906) or 

 at least near the middle of the eleven-year period (see 1896). In 

 the last period, 1902 to 1913, there was a middle minimum so much 



Figure 88. Temperature differences (in degrees Centigrade) between the 

 warmest and coolest months of the year in four regions of the United States 

 of America. I : in the most westerly states on the Pacific Coast. II : in the 

 states on the Mexican Gulf. Ill : in the most easterly states on the Atlantic 

 Coast. IV: in the inner states. 



deeper than the others that at this period the curve IV on the whole 

 goes oppositely to the sun spot curve. 



In the curves II and III for the Gulf states and for the Atlantic 

 coast states there is an indication of a similar halving of the eleven- 

 year period, with some displacement of phase. 



For these four regions of the United States we have also studied 

 the variations of the average temperatures for the summer and for 

 the winter. As representing the winter we have used the months 

 December, January, and February, and for the summer, June, July, 



