PRESIDENTIAL ADDRESS. 



19 





Mean. 



Maximum. 



Minimum 



January 



... 70*9 



72*3 



69*1 



February 



... 71*2 



72*4 



70*0 



March 



... 70*5 



72*1 



68'7 



April 



... 68'4 



70-5 



66*3 



May 



... 64*6 



67*0 



61*8 



June 



... 60*4 



62*5 



57*5 



July 



... 57-0 



59*3 



55*8 



August 



... 57'9 



59*3 



56*6 



September 



... 60*2 



61*5 



58*9 



October 



... 63*1 



64*6 



61*8 



November 



... 66*4 



68*2 



64-5 



December 



... 70'3 



71*4 



66*9 



Such observations, limited to a single spot, and to a 

 single hour, present too narrow a view of the water climate. 

 Probably they convey a better idea of the maxima than of 

 the minima. In shallow water, and in the remoter reaches 

 of the harbour, the temperature might be warmer in sum- 

 mer and colder in winter than this. 



The decennial maximum 75*5 was reached on January 

 15th and 20th, 1887; the minimum 50*1 occurred on July 

 20th, 1881. The hottest days of the year happen in either 

 December, January, February or March, and the coldest 

 days either in July or August. February has the highest 

 mean temperature and July the lowest. It is noticeable 

 that the warmest months are the most equable, the tem- 

 perature sometimes oscillating only from one to two degrees, 

 while the coldest months are the most variable. Compared 

 with the range of temperatures noted at biological stations 

 abroad, the Sydney records are singularly level. Thus at 

 Woods Hole in the western Atlantic the temperature 

 ranges from below freezing to 70°, and in the Bay of San 

 Francisco from 42° to 69V Off Plymouth, England, some 



1 Sumner, Bull. U.S. Fisheries, xxxi, 1913, p. 436, Id. Univ. Calif. Zool. 

 Publ., xiv, 1914, p. 99. 



