224 . NATURAL HISTORY 
and partial ones, in proportion to the agitations of the eartn, ^as 
was the cafe of Lifbon in the late dreadful earthquake of November 
1 7 5 5) caverns continue open as before, and the inflammable 
matter is at liberty to range, ferment, and expand itfelf, and confe- 
quently produces new and frequent emotions of the earth, and that 
this is likely ftill to be the cafe till the cavernous pafiages below are 
clofed up by the fubddence of the grounds near the furface, 
Laftly, Thefe fwampy pits of marfli earth retaining their moif- 
ture, protected as they are from all exhalation by the fea and fands 
above them, are in the date of quagmires ; and when the fands are 
difperfed and thinned, (as will happen by the dorms and the out- 
hall of the fea) the quagmire is not fufficiently covered : this is the 
reafon that thefe and other fands are occadonally quick and finking, 
and give way to any incumbent predure ; but the fands in this place 
are never dangerous, as they are in other places, where the interred 
bogs are more lax and deeper . 
SECT. in. From trees let us defcend to flirubs. It is fuggefted that the 
Of flirubs. fweet-brier, or eglantine c , does not grow naturally in Cornwall , 
but this is a great midake, as, from experience, I can aver, having 
plucked this perfumed plant out of the hedges in the neighbour- 
hood of Mount’s Bay, and tranfplanted them into my own garden, 
where they dower in as great perfection as any where, and may be 
eafily multiplied by feeds, dips, or cuttings, dhe furze-bufh (01 
ulex) grows in great plenty, and affords cheap fuel to the poor. 
We have two forts of it, one a dwarf-furze of a fmall prickle and 
branch, in the coarfed, fhallowed foil, which we call Cormfh furze, 
never growing three feet high, dowering in autumn; the other 
dve, fix, and eight feet high, more woody, thriving bed in a 
deeper and more tenacious foil, this makes a more lading and 
dercer dre ; we call it French furze ; it is the genifta fpinofa 
vulgaris d , and bloffoms in the fpring. Its leaves are of a deep 
green, and its yellow dowers fo numerous and fweet, that iome 
gentlemen have raifed hedges of it in their gardens, but the leaves 
are foon cad, and the hedge grows bare and dicky, fo that expe- 
rience, I think, does not favour the attempt. Among the Cormfh 
furze is great plenty of the common heath, (or erica) a plant 
which by its roots makes the turves cut up for fuel much tne better, 
but its branches impede and weaken the furze. The Danes drew 
an intoxicating liquor from the erica , and fome think they accounted 
it fo precious as to ereCt lines of large dones for boundaries to limit 
the properties of this plant \ 
4 See page 75. 
* Rofa filveftris foliis odoratis, Ray. Stirp. Brit, 
page 454. 3ded. 
4 Ray, ibid, page 4.75. 
« Hift. of Cork, vol II. page 358. 
The 
