592 PHILOSOPHICAL TRANSACTIONS. [aNNO 1755, 



rounding fire condensed by degrees ; which must increase their specific gravity, 

 and lessen their repulsive power : by which means they must both descend and 

 approach each other, till at last they form dense visible clouds ; and these clouds 

 are also accumulated by other succeeding vapours, of like specific gravity, till 

 they form clouds, which are often several hundied yards in depth, as is often seen 

 in passing through them up the sides of very high mountains. In clouds of such 

 depth, he thinks the coalition of their particles to form drops, may arise from 

 their motion, and the order of specific gravity. Hence he thinks the excess of 

 electrical fluid will run off among the other particles; by which means the en- 

 larged particles have their specific gravity increased, and are enabled to descend 

 to a lower region of the air. And the more particles they impinge on, in their 

 descent, the more their specific gravity and velocity will be increased ; and the 

 more their velocity is increased, the more particles will they impinge on, till they 

 fall from the clouds in drops; whose size will be according to the depth and den- 

 sity of the cloud they have passed through. 



Having remarked on several of the other particulars above enumerated, in a 

 diffuse and uninteresting manner, Mr. E. then adverts to something of land- 

 breezes and sea-breezes, a phenomenon which sometimes happens in fair settled 

 weather, when the wind blows out from the land at night, and in from the sea at 

 day-time. The land-breeze is occasioned by the descent of the clouds, and the 

 particular formation of the land; for if the land rise into a hilly country from 

 the sea, when the clouds and vapours ascend at night, which they often do by 

 the electrical fluid being condensed, they must press the air down the land to- 

 ward the sea in their fall; as may appear from the smoke of any fire running 

 down the side of a hill, in the evening of a damp day, when the clouds are on 

 the descent. And the sea-breeze is occasioned by the clouds ascending in the 

 day-time, which must impel the incumbent air upwards, and make room for the 

 sea-breeze to flow in ; but, beside the mere ascent of clouds, there is an exceed- 

 ingly greater quantity of vapour raised from the land than from the sea. For the 

 same extent of land has an exceedingly greater surface than the same extent of sea ; 

 which may appear from the various forms of vegetables and animals, &c. and 

 the greater the surface, the greater will be the evaporation. Beside, the more 

 irregular these surfaces are, the greater will be the reflection and refraction of 

 the sun's beams, which will increase their power. And it is also necessary that 

 the evaporation should be much greater from vegetable and animal fluids, than 

 from fluids in a quiescent state, to carry on a circulation for the great work of 

 nutrition. Now the ascent of these vapours must beget a circulation of the air 

 inward from the sea ; in the same manner as the ascent of vapours fi-om any fire 

 brings in the air below to that fire. 



As to water-spouts, he says they are oddly described by the learned, as being 



