256 Mr Black cni the CUmaie 



of the opposite winds above mentioned, analogous phenomena 

 ai*e sometimes observed at sea, and out of the immediate influ- 

 ence of the land. Thus a wind, blowing from the northern 

 shores of the Mediterranean, may be in perfect equilibrium with 

 the land it leaves ; yet, when it encounters the southerly current 

 at sea, will be in a relatively positive state of electricity. The 

 consequence of this collision will be, a transference of the fluid 

 from the north to the south current ; and according to the ex- 

 tent of the electric difference between them, will be the amount 

 of the resulting phenomena. From the observations of five 

 years, I have always found, that, when electrical phenomena ap- 

 peared, a change of wind from N. to S., or from opposite points 

 near to the meridional line, invariably occurred. One difference 

 has been noticed in the character of these phenomena, that, when 

 they were developed in the vicinity of high land, thunder ac- 

 companied them ; but, at sea, it seldom or never occurred, — the 

 transfer of the electric fluid, in this last situation, appearing to 

 take place in a more gradual and less violent manner, than when 

 the peaks of mountains facilitated those local accumulations, 

 whose disturbance creates such intense results. 



As a general observation on this part of the meteorology of 

 the Mediterranean, it may be inferred, that winds or currents of 

 vapour, of some continuance, from an extent of sea, are nega- 

 tively charged with electricity ; and those from the land, and 

 especially from hilly countries, are relatively in 2l positive condi- 

 tion. 



During the period in which I have been in the eastern section 

 of the Mediterranean, abundant opportunities have occurred of 

 witnessing the effects of localities on the temperature and humi- 

 dity of the winds, even when they continued to blow from the 

 same quarter of the horizon ; as well as of observing how the 

 climates of particular places are aff*ected by the nature and direc- 

 tion of the winds, and the atmospherical impregnations prevail- 

 ing at the time. These opportunities have resulted from being 

 often one day to the northward, and the next to the southward, 

 of land, with the continuance of the same wind ; at another day, 

 with a great scope of sea, and on the following one with an ex- 

 tent of land, in the direction of the same wind ; while frequent 

 visits to different places and anchorages, in different seasons of 



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