found of it full of a fpecies o f agate, ilreaked with red,
blue, white, green, and black, that take a very good po-
lifh, but thefe colours are accidental, and difappear
by calcination. No acid will diifolve it, or caufe any
eff'ervefcence; when calcined, it burns in the water
withNjnore violence than true limeitone, and mixed with
the pebble or coarfe fand near Madrid, makes an excellent
material for building, though it does not anfwer
fo well with the fine fand o f the river. It is impoffible
to fufe this flint alone, or any other found in limy or
argillaceous earths, no more than the different kinds O 1
o f agates, cornelians and rock cryftal, but they calcine
by themfelves; that is are turned into lime and fufe very
Veil mixed with the fixed alkali of Barilla, or with lead,
the eafieft to fufe of all metals, and change into the En-
glifh flint glafs, which is by far the belt hitherto known.
Many naturalifts, according to Mr. Bowles have followed
this erroneous opinion refpefling flint, and amongft
the reft Mr. de Reaumur. Linneus in his Syftema Naturae,
fays, “ Silex nafcitur in montium cretaceorum rimis, uti
quarzum in rimis Saxorum,” but we have only to open our
eyes, to be fully convinced of the fallacy of this affer-
tion, when we contemplate the numerous beds of flint
near Madrid, and in different parts o f Spain, and Italy,
feparated from all cretaceous matter. The abate For-
tis, in his late travels into Dalmatia, found the flint
there, quite different from the defcriptions o f former
; naturalifts,
naturalifts, and adds, “ I have often feen the flint in the
very ad: as I may fay o f pafling from the calcareous ftate
to the filiceous, and particularly I have often found flint
envelloped in volcanic matter. I have formed a feries of
thefe progreffes, which I have Ihewn to fome o f my
friends [a)." I ' V-- ■ ■.' Hu ' •
In the environs of Madrid there are above two hundred
villages, but few can be feen on account o f the inequality
of the ground, the country being broken up by continual
gullies, and various changes of afped, occafioned
by torrents, and other cafual accidents, in a country little
cultivated, and abandoned to every viciflitude of
feafon. Near the town they chiefly fow barley, and
here and there have fome trifling vineyards. Their
tillage is much the fame as in Old Caftile, that is, juft
to fcratch up the earth and fcatter the feed at random,
then to cover it over with a fimilar indifference, and
wait for the coming o f the poor labourers from Galicia,
to get in their harveft. The farmers pretend that i f
they were to make ufe of a ftronger plough, they ihould
have lefs corn. Mr. Bowles next reproaches the Spaniards
for pafling over incidence their countryman Don
Jofeph Lucadelo, a gentleman o f Aragon, who had invented
a curious plough much efteemed by foreign nations,
who had taken the' merit o f the invention to
{a} Travels into Dalmatia by the abate-Fortis, tranflated' into Englilh. London,
themfelves,