138 PHYSICAL GEOGRAPHY. 



Diagram Fis a comparison of the extreme maximum and minimum 

 temperatures of the 7 A. M., 2 p. M., and 9 P. M. observations at Claremont 

 and Stratford for 1 867 and 1 868. These places were selected for compari- 

 son, since Claremont is the most southern point in the Connecticut valley 

 where observations have been taken, and Stratford the most northern. 

 It is noticeable that, while the minimum of Stratford is less than at Clare- 

 mont, the maximum is greater at Stratford than at Claremont. This is 

 the general rule, though there are exceptions to both. 



Diagram VI is a comparison of the monthly mean temperatures of 

 Exeter, Claremont, and Stratford for 1864. It will be observed that, in 

 the extreme maximum and minimum, the difference is greatest in winter 

 and least in summer; but in the monthly mean, that the difference 

 between Claremont and Stratford is greatest in summer and least in 

 winter. 



Diagram VII is a comparison of the monthly mean temperatures of 

 Mt. Washington and Lunenburg, Vt. 



Diagram VIII is a comparison of the maximum and minimum tem- 

 peratures at Exeter, Manchester, Claremont, North Bridgeton, Me., and 

 St. Johnsbury, Vt., during the cold period of January, 1861. 



Diagram IX is a comparison of maximum and minimum mean temper- 

 atures for the cold period of January, 1871, of Mt. Washington, Tamworth, 

 Contoocookville, Stratford, and Whitefield. 



Diagram X shows graphically the difference in the velocity of the wind 

 at the station on the summit of Mt. Washington, and a station at the 

 depot of the Mt. Washington Railway, 2,677 ^ eet below the summit. The 

 figures on the left and right are miles per hour. 



