12 
NATURAL HISTORY 
winter, in fuch counties, imparting to vegetation a vigorous Ipring, 
unknown to the equable feafons of Cornwall. In fhort, the fea- 
fons with us in Cornwall, are like the Neap-tides, they neither 
ebb nor flow with any great energy : the heat of the atmofphere 
neither retires fo far from us in winter, nor advances to that height 
in fummer, as it does in the more inland counties : confequently, 
our fummers, though we lie fo far to the fouth, are not hot; for 
there is always a fea breeze flowing towards the land, and the air 
of the fea is never fo hot, caeteris paribus, as the air of the land; 
becaufe the ftrong reflection of the fun beams from the land 
almoft doubles the heat; the fun beams are alfo detain’d in 
the vales and hollows, in the midland parts, (circumftances not 
common to the fea and fea, coafts) which have the fame effeCt 
upon the air (though in a lefs degree) as concave mirrors, always 
heating, though not always burning : It is much hotter there- 
fore in the midland parts of England, during the fummer, than 
in Cornwall ; this may make their harvefts earlier, and their fruits 
generally of a higher relifh than with us, (in equal circumftan- 
ces, I mean, as to drought and moiflure, flerility and fatnefs) 
but the air is more temperate and lefs fultry with us, the fea 
air equally aflwaging the heats of fummer, and moderating the 
winter colds. 
Eft ubi plus tepeant Hyemes? ubi gratior aura 
Leniat et rabiem Canis, et momenta Leonis ? 
Hor. Epift. lib. i. 
Meteors ^and there are fo many mines in Cornwall, and moft of them 
Lightning. yield fulphur, vitriol, mundic, and goffan x , they cannot but affeCt 
the air with their fleams in proportion to the quantity yielded by 
the mine, and the facility with which their parts feparate and 
afcend into the Atmofphere. Thefe mineral vapours afcend fo 
copioufly out of fome of our Lodes or veins of metal, and confift 
of fuch inflammable parts as to take fire, and appear in flame 
over the Lodes from which they rife, and it is a common opinion 
among Tinners, efpecially thofe of more than ordinary fpeculation, 
that where little flames of light are feen in the night time, there a 
prolperous Lode lies underneath, but indeed the lights which are 
feen in the night are much oftner ignes fatui ", and have nothing to 
inform us of, but that being deferted by the fun that rais’d them, 
their own weight confines them to their low fituation, where they 
yield their electrical Are, and will always do fo, whenever proper 
motion and materials concur. 
On 
* An iron, ochreous, ftony clay. 
7 Called by the Coraifn, Jack with the Lanthorn. 
