METEOROLOGICAL OBSERVATIONS. 



Anmdaii Ineqoality in the Diukmal Amplitude of the Tempeeatdre at Pokt Foulke. 



185 



90 



11 1 L 1 1 1 1 1 



III 1 



8 



; A 



- 



6 

 5 

 4 

 3 

 2 





1 



I 1 1 1 1 I 1 1 1 



, y,- 





January 



February 



March. 



April 



May 



June 



July 



August 



September 



October 

 November 

 December 

 January 



The daily range is greatest iii spring, in March it attains its maximum value, 

 then falling a little and rising again in May, it diminishes till December, when it 

 reaches its minimum value. The great rise in spring is due to the immediate effect 

 of the sun he/ore it has power enough to melt a sufficient quantity of ice to check 

 it. The small depression of the curve, in the spring and early summer, and shovrai 

 by the three locaHties discussed, is most likely due to the increasing vapor. A more 

 full material for discussion would probably bring out a small increase ui the range 

 late in summer or early in autumn, at a time when the freezing process again comes 

 into powerful action. Of such an increase we have at present only a trace. 



In the following expression of the diurnal fluctuation during the whole year, the 

 angle Q counts from midnight at the rate of 15° an hour. To this expression those 

 for the other localities were added for comparison. 



Port Foulke, t = + l°.51 sin (e + 235° 8') + 0°.02 sin (29 + 195°) + Oo.ll sin (39 + 148°) 

 Van Rensselaer, t = + 1.85 sin (O + 244 55 ) + 0.08 sin (2b + 91 ) + 0.03 sin (39 + 308 ) 

 Port Kennedy, t = + 2.02 sin (9 + 252 5T ) + 0.25 sin (29 + 117 ) + 0.09 sin (39 + 251 ) 

 The probable error of any single representation, for Port Foulke, is +0°.08. 



DiDKNAL Fluctuation of the Tempekatdee. Mean Annual Value. 

 I I 1 I I I I I 



1 1 I I I I I 1 I I I i 1 I 



According to the formula the temperature rises tiU 2g P. M., when it attains its 

 greatest value ; it reaches its lowest value at 2| A. M., and its average value about 

 8 A. M. and 8 P. M. 



24 November, 1865. 



