I04 NATURAL HISTORY 
the moifture of weather, improper hones, and broken cement, out 
by firft imbibing ftrongly, then arrefting and detaining the damps, 
and draining the cement fo as that it cannot tranfmit its dampnefs 
through the walls : this brick will do till it is fatu rated with redun- 
dant moifture, and then it obviates damps no longer ; and it lodows, 
that the more our granites partake of the nature of bricks, the 
dryer they are for walling ; on the other hand, the more tney admit 
and condenfe, and the eafier they quit and difperfe the moifture 
they receive, the greater damps they occafion, keeping the body of 
the cement, and every thing contiguous, in a continual unwhole- 
fome ftate of moifture. 
CHAP. X. 
Of Stones of Ornament and Curio fty , viz. Pebbles, Flints, Porphyry , 
Talc, Stala&ites , Afbeftos , and fmall Gems found in Cornwall. 
T HERE are no gravel pits where pebbles and flints lie in 
heaps and ftrata at prefent difcovered in Cornwall, which 
have reached my knowledge, but nature has made fufficient amends 
by beftrewing the beach of our bays and creeks with an infinite 
number of pebbles, flints, and nodules. Here therefore the curi- 
ous Naturalift will find, fpread as it were for his better oofervation, 
a large collodion, wherein, though there are many duplicates, yet 
is there a greater diverfity of curious ftones on a beach or a few 
furlongs, than are to be found in fome hundreds of miles, travelled 
over in the inland country. When the learned travel, they only 
take notice of, and colled what is rare to them, or not yet de- 
ferred ; whence it happens oftentimes, that thofe things which 
are reckoned among the moft entertaining produds of nature in 
other countries, lie on our own fliores negleded, merely becaufe 
they are well known to the Literati, and found in other places by 
the occafional vifitors of this, and other particular counties. 
I fhall range the pebbles by the colour of their grounds as I have 
done before by the granites. 
sect. i. N°. i. Of the white pebbles fbme are veined like marble, fbme 
clouded with a lively flefh-colour, fome variegated with purple^ and 
other fpots, as well as veined, others charged with black pebbles, 
fome rough and gritty to the touch, others fmooth, fome tranfpa- 
rent as rock cryftal. Of this laft fort 1 have feen a feal cut out or 
(what the lapidaries call) Pebble Cryftal, extreamly bright and clear: 
the pebble was found, as I am informed, on the top of Routor, 
