NATURAL HISTORY of NORWAY. 25 



where, but in this I am inclined to think the found impofes on 

 our judgment, the noife and eccho of winds and thunder being 

 much louder among the lofty mountains than in the plain coun- 

 try. This difference I have found, that fometimes, tho' feldom, 

 thunder is heard at Bergen in the winter, doubtlefs becaufe that 

 feafon of the year is, as hath been already fhewn, attended with 

 very little pure cold, but rather with a raw air, and of courfe 

 with more rain than fnow and hail. 



SECT. XIL 



As to the humidity of the air, rains being fo unufualiy frequent Rains and 

 at Bergen, and for fome miles round, as to be proverbial among w a e ftSdT 

 the Dutch ; I apprehend the caufe may be derived not only from 

 the high mountains, there being in other parts of this diocefe See a view oJf 

 much higher mountains, with much lefs rain, but rather from the 

 many narrow valleys and creeks in the neighbourhood, which be- 

 come foon filled with their own evaporations as well as thofe 

 from the fea, and thefe are not foon difpelled by the wind or fun- 

 mine, except in the heat of fummer, when the fun has fufficient 

 power to draw them up into the open air above the fummits of 

 the mountains, there to be feparated and difpelled by the wind. 

 Whereas, on the contrary, in other feafons of the year, when the 

 power of the folar rays is weakened, the vapours cannot rife to any 

 confiderable height above the horizon f . Hence we fee them hover 

 like rain-clouds, and reft not only on the tops of the mountains, but 

 often hang about their fides, infomuch, that the top may be clear, 

 and the middle of the declivity be covered with thefe rain- clouds : 

 arid when travellers or peafants happen to be furprized among them, 

 which is a common cafe, their fight is fo obftru&ed, as not to fee 

 their way ; they breath with difficulty, grow wet and cold, and un- 



* If the old opinion, of the fun's exhaling the vapours upwards, fhould not prevail 

 againft the new, which holds, that fmall veiicles of air are impelled upwards, and 

 being lighter than the lower air, float in it. Wolff's Phyfic. Cap. v. Se£t. o^y. Yet 

 my conjecture on the rain at Bergen ftill keeps its ground ; for the eminent naturalift 

 juft cited, allows that the winter-vapours are heavier, and as fuch fink lower into 

 the atmofphere, or cannot afcend fo high, the teguments of their fmall veficles be- 

 ing then condenfed, fo that the effect produced is the fame. His words are, Sect. 254, 

 " The vapours being rarified in the heat of fummer, they then rife to a great height 

 in the air :" Again, " the groffer vapours, having a thick tegument and a fmall ca- 

 vity, are heavier, and remain in the lower region of the air, this being of a more 

 denfe nature than the upper ; thus in winter, the vapours being condenfed by the 

 cold during that feafon, remain in the lower parts of the atmofphere. 



lefs 



