44 



index varies from an initial value of 122 to a final value of 

 81, with maxima for the peri ods /beginning July 16 and August 14/. 

 Inspection of these two graphs for OaKland shov/s that the 

 direction of slope is the same from period to period, for the 

 greater part of the season. ?or Ohewsville the two graphs agree 

 in direction of slope throughout the entire season except 

 betv/een the periods beginning August 25 and Sept. 8. Both curve 

 graphs are approximately parallel to the graph of temperature 

 efficiency for this station from the period beginning July 14 

 to the period beginning August 25 and both have a dovmward 

 slope, in general, from fche beginning to the end of the season, 

 and they agree in direction of slope from the period beginning 

 June 15 to that beginning October 8. The maximum o-f the evap- 

 oration graph for the period beginning July 27 corresponds to 

 a secondary minimium in the gra'oh of temperature efficiencgr 

 for College. The graph of the evaporating power of the air 

 has a primary maximum for the second period fbeginning May 28) 

 and a well-iparked secondary maximum for the period beginning 

 July 22. IIo sunshine -^ t ^ >-■. -e available for this station. p-^r 

 Baltimore the tv/o graphs in question agree in direction of 

 slope up to the period beginning July 9 after which the evap- 

 oration graph -ascends to a secondary maximum -n'} .-^h corresponds, 

 in a very rough way, to the doiible maxiyima of the temperature 

 efficiency graph. For Darlington the general statements made 

 at the beginning of •<-'•■' s ■''iscussion hold t.hroughout the gre^+p-'- 

 part of the season. The atraometric values for this station 

 are relatively very low; all but tv.'o of them ar^: lower than 

 the seasonal average employed as unity ' - '■'-■ --'^sent study. 



