62 BROOKLYN BOTANIC GARDEN MEMOIRS 



Island.* Full details of the temperature of the sea water at the eastern 

 and western ends of Long Island will be published later in another con- 

 nection. . 



The Livingston and Shreve direct summation of normal daily mean 

 temperature for the period of the frostless season shows for Montauk 

 (Block Island) : 



Above 0° F. Above 32° F. Above 39° F.f Above 50° F 



12,946 5.970 4,444 2,264 



Rainfall (including snow) 

 Annual 41-79 inches, which is 89% of the wettest Long 



Island locality. 

 Amount of rainfall during the pe- 

 riod of effective temperature 27.02 inches, which is 91% of the wettest Long 



Island locality during this period. 



Evaporating Power of the Air. 



Of the different types of evaporimeter it was decided to use the Living" 

 ston black and white atmometer, largely because the readings from them 

 are more easily comparable to the results of other workers. 



All the records were taken with instruments mounted in the usual way, 

 but the bottles in every case (except one to be noted specially) were buried 

 up to the neck. Some of the records were taken before the mercury valve 

 to prevent intake of water had been proposed, but in these records daily 

 readings were made for rather brief periods in September 1919, and May 

 1920. During 1921 the instruments ran continuously from July 15 to 

 September 24, and in 1922 from July 27 to August 18. Both the 1921 and 

 1922 readings were made at intervals of several days, with mercury valve 

 instruments.! In all cases the accompanying graphs (Figs. 22-25) have 

 been translated to the rate per day (the number of cc. per day) of evapor- 

 ation. 



* There is a brief account of the sea breeze on eastern Long Island and of the effect 

 of this cool sea water on the climate of the Island, both by Ernest S. Clowes of Bridgehamp- 

 ton in Monthly Weather Review for July 19 17. They show very clearly the effect on the 

 temperature, particularly near the shore, of the sea breeze blowing in from the cool water. 



t The nearest figure to the so-called "effective temperature " used above, which is 

 merely the addition of all the degrees of temperature in excess of 43°, which has been used 

 by many other workers as a basis. 



jThe 1 92 1 instruments were supplied with a mercury valve held in place by glass wool. 

 A decided improvement in this was devised by Mr. Frederick A. Musch of New Haven, 

 who kindly made a series of readings for me in the pitch pine region at North Haven, 

 Connecticut. Mr. Musch's ingenious modification of the usual tubing made the mercury 

 valve a most satisfactory device for the Livingston atmometer. See Science 57: 26-28. 

 1923. 



