THUNDER STORMS. gt 
from them by the furface of the earth; till at length that 
whole region of the atmofphere has its ele€trical capacity 
enlarged, thereby becoming negatively electrifed, or ina 
craving ftate, as obferved before. On the contrary the 
fun’s rays which fall upon the furface of the fea, efpecially: 
when ruffled by wind, chiefly enter that tranfparent me- 
dium, in which they are refracted and irrecoverably ab- 
forbed; very few, comparatively, being reflected; whence 
very little heat can be reverberated from that element to 
warm the incumbent air, which is fenfibly affected only by 
the paflage of the fun’s dire& rays through it, unlefs the 
weather be calm and the furface very {mooth*. Befides, it 
is colder at fea than afhore in the fummer feafon, when, and 
when only thunder fhowers are frequent, and indeed 
warmer in the winter, for the following reafon, viz. as the 
fea is every moment changing its furface, neither heat nor 
cold can affeé it fo foon as they do the furface of the earth, 
which continues the fame. 
The air over the land, when thoroughly heated and ra- 
refied, naturally afcends into the higher regions, while the 
denfer air from the fea neceffarily flows in and takes its 
place. Hence, probably, the eafterly winds which ufually 
fpring up near the middle of the day, after a fultry 
morning. 
This body of warm air afcends till it arrives at that re- 
gion of the atmofphere in which thunder clouds are form- 
ed; while the vapors which are wafted to the continent 
by the eaftern current, being attracted by this now fupe- 
rior air which demands a fupply of the electric fluid, con- 
2 tinually 
* Ina perfect calm the furface of the fea atts like a mirror upon the fun’s rays, {trongly re- 
verberating them back into the atmofphere, when the heat is as fenfible upon water as upon 
the dry land. But whenever that furface becomes agitated and broken by the force of wind 
acting upon it, thofe rays, by perpetually impinging upon an infinite variety of new formed, 
fluctuating furfaces undergo innumerable refractions, in all direftions, whereby they are ab- 
forbed and loft within the fluid mafs in fome proportion to the violence of the agitation. Ac- 
cordingly when the weather is ferene and calm, the furface like a looking-glafs refle&ts the phe- 
nomena of the fky over head; upon the firft fpringing up of a breeze it changes to a light blue, 
which deepens to a fine fky-blue as the wind rifes, to a deeper fea-green in a brifk gale, and to 
a fuilen blacknefs in a ftorm, excepting where the waves are interfperfed with white heads of 
foam, which, by contraft, only render the fcene more gloomy. 
