ItB 



< 



^^ i 



. t 



f 





) 



1^ 



•V 



1 



l- 



\L 



V 



*fr» 



h 



« . 



i 



i 





r 



f 





J 



,i to 



i 



lit-: ft 



•J 1" 



>*" 



tii^k 



! 



n J 



* 



Sect. IX. 1 



J 



METEOROLOGY. 



Br 



O 



fall 





Local inquii-y and consultation of records must 



due care bein^ 



here stand in lieu of personal observation, 



taken to rely on none but unexceptionable evidence. 



The phenomena of dew are of more interest, and can be 

 better studied on shore than at sea. The amount of dew 

 collected by a given surface of any bibulous radiant, as 



cotton, &c., in clear nights, i 



rt 



perft 



the sky, and on the level of the soil, should be registered. 

 If accompanied with ohservations of the depression of the 

 terrestrial radiant thermometer, and also of the hv^Ti 



meter, such observations would acquire additional value. 



The temperature of the soil under the direct influence 

 of the sun as indicated by a thermometer barely covered 

 with dry earth, is an element of importance to the bota- 

 nist, and may be recommended as an apt accompaniment 

 to actinometric observations. The thermometer used 

 should have a scale reading at least to 180" Fahr. 



Meteorological registers kept by persons of credit at 

 places where the ship may remain or touch, should be 

 enquired for and copied, or the originals procured, and 

 the instruments with which they have been made carefully 

 compared, and the height of their stations above the sea- 

 level ascertained. 



JVaterspouts, BuWs-eije Squalls^ Whirlit 



The 



, and from 



transition from the mere eddy to the whirlwind 

 the whirlwind to the waterspout {Trornhe), should be 

 traced if possible. All circumstances from the first trace 

 or prognostic to their final dissipation should be minutely 

 noticed, especially the movements of the sea under their 

 influence, and the direction of their rotation. At what 

 distance is the whirling motion of the air perceptible? 

 AVhat are the indications of the barometer durin"- their 



p 



i 



i 



\ 



t-" 



V _L 



_-"t--r* 



