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whofe exploits againftthe Zamorin approach more nearly 
to the atchievements of Amadis or Palmerin than any 
other parallel which hiftory can fupply : the poem, how¬ 
ever, is in honour of a Jefuit who fuff'ered martyrdom in 
Japan, and to whom the poet was related. 
Pereira has written without any appropriate learning. 
Except the names of the idols and the bonzes, there is no 
allufion to any rite or cuftom of the country. There 
are, however, fome curious paflages in the poem, parti¬ 
cularly a perfonification of Amor Vitae, and fome of real 
merit. Were a collection of the modern Latin poets to 
made, the Paciecis ought undoubtedly to be included. 
R. S. in Gen. Biop;. 
PERE'IRA DE SU'SA, a town of Portugal, in the 
province of Beira: twenty-three miles north-eaft of Bra- 
gan$a Nova, and eighteen fouth-eaft of Oporto. 
PE'REK, a town of Perfia, in the province of Farfiftan : 
fourteen miles north of Darabgherd. 
PER'EKOP, a fortrefs of Ruffia, in the province of 
Tauris, on the ifthmus which joins thepeninfula to the 
continent, and which has always been reckoned the key 
to the whole country. Its name is Sclavonian, and fig- 
nifies “ a cut made through” a place ; being derived from 
a ditch dug here, in very remote ages, acrofs the neck of 
land at the entrance of the Crimea, for the fecurity of 
thepeninfula; and which has been from time to time re¬ 
paired, and at length fortified. On this account the 
Greeks called it Taphros, or Taphrce, and the Turks and 
Tartars Or ; which have pretty much the fame fignifica- 
tion with Perekop. The houfes here are but mean. In 
the years 1638 and 1736, the Ruffians rook it; at the lad 
of which times, the whole Turkifh garrifon, confiding 
of 2554 men, were made prifoners of war. Though the 
Ruffians demolifhed the place, the Tartars took the pains 
to rebuild it. In 1771, it was again taken by the Ruf¬ 
fians, when the garrifon furrendered prifoners of war. In 
1783 it was finally ceded to Ruffia, with the reft of the 
Crimea, by the abdication of the khan. It is 132 miles 
fouth-fouth-weft of Ekaterinoflav, and 220 weft-fouth- 
weft of Azof. Lat. 46. 4. N. Ion. 33. 20. E. 
PEREKOPSKA'IA, a town of Ruffia, in the country 
of the Coffacks, on the Don : forty-eight miles fouth of 
Archaainfkaia. 
PEREL'LI (Thomas), a very able Italian mathema¬ 
tician, was born in 1704 at Florence, where his father was 
an advocate. He received the early part of his education 
at his native place, under the Jefuits ; and, being deftined 
by his father for the law, w'as fent to Pifa, where he at¬ 
tended the celebrated Averani, but without neglecting 
other branches of ftudy, for which he feemed to be better 
fitted, and particularly the mathematics. In this depart¬ 
ment he made fo great progrefs, without any affiftance, 
that he attracted the notice of the celebrate'd Guido 
Grandi, who received him into his monaftery of St. Mi¬ 
chael, and communicated to him his writings on algebra. 
Having abandoned the law, he applied to philofophy and 
medicine; and, at length, fucceeded Zambeccari in the 
chair of anatomy. The death of his father having obli¬ 
ged him to return to Florence, he had an opportunity 
not only of profecuting his mathematical refearches, but 
of applying to botany, Greek and Roman literature, an¬ 
cient and modern hiftory, and the examination of the 
monuments of antiquity in the Medicean collection. He 
frequently travelled with the celebrated Micheli, then 
confidered as the Tournefort of Italy, and participated 
with him in the difeovery of many new plants. He then 
removed to Bologna, where he formed an acquaintance 
with Manfredi, Beccari, Zanotti, and other eminent men. 
After various literary tours, he offered his fervices to 
the prefident of the Univerfity of Pifa, and in 1739 was 
made leCturer on aftronomy. At this time aftronomy 
was in a very negleCted ftate in that inftitution ; and, 
though a new obfervatory had been ereCted by the muni¬ 
ficence of the duke of Tufcany, little progrefs had been 
made in the ftudy of that fcience. Perelli, therefore, in 
his inaugural difeourfe, written in elegant Latin, ftiowed 
with great force and energy the necelfity of reltoring af¬ 
tronomy to its former dignity. He alfo endeavoured to 
procure for the obfervatory the beft inftruments, made 
by the tnoft eminent Englifti artifts; and his zeal was 
w ell feconded by the liberality of Francis II. who refilled 
no expenfe which could contribute to the benefit of his 
ftates. But Perelli had too fervid an imagination to bea 
laborious and patient obferver. A few obfervations of 
eclipfes, a part of Ptolemy’s Alnugeil tranflated by him 
into elegant Latin, and a fecond preface to obfervations 
made by his afliftanr, containing a Hiftory of the Obfer¬ 
vatory of Pifa, were his only writings of the aftronomi- 
cal clafs. 
His fame, however, was foon fpread beyond the boun¬ 
daries of Italy. The folution of an optical problem, 
“ To find a curve of fuch a nature, that the rays of light 
which fall upon it fhal 1 always proceed, after two reflec¬ 
tions, to one point in the middle,” tranfmitted to the 
Academy of Sciences at Paris by the French minifter at 
Florence, convinced Clairault, Bouguer, and Lalande, 
that he was fit to be afiociated with mathematicians of 
the firft clafs. The approbation of thefe eminent judges 
incited him to apply with greater diligence to geometry ; 
and befides other difeoveries, he gave a folution of that 
curious problem, “ To find the point of greateft illumina¬ 
tion in a plane, fuppofing that there are placed at any dis¬ 
tance from it a certain number of lights.” How well Pe¬ 
relli was acquainted with fynthefis, may be feen by the 
folution of that problem in which it is required “ To find 
the radius of a circle that fhall touch externally three 
other circles, the centres and radii of which are known ;” 
a problem which New'ton thought worthy of a place in 
his Univerfal Arithmetic, and which,after many folutions, 
both ancient and modern, was folved by our author with 
mafterly and elegant fimplicity. 
One of the great fervices rendered by Perelli to his 
country, was the happy application which he made of 
his mathematical knowledge to hydroftatics, hydraulics, 
and hydraulic architecture. Unfortunately for Italy, it 
has often need of fome fuperior genius to regulate the 
abundance of its waters, and provide for the fecurity of 
its inhabitants, particularly where the natural courfes of 
the rivers have been fo changed, either by the different 
interefts of the princes who rule in it, or the operations 
undertaken according to their caprice, that, without the 
application of artificial means, they cannot be prevented 
from inundating whole provinces. This necelfity has 
produced a fcience which the Italians exclufively claim as 
their own ; and in which, from the opportunities they 
have of acquiring practical knowledge, they are undoubt¬ 
edly fuperior to the mathematicians of other countries. 
Perelli, formed in the fchool of Grandi and Manfredi, 
to whom this fcience was fo much indebted, is entitled 
to the honour of having greatly contributed to improve 
it ; and it may be faid, that after the death of thefe two 
eminent men, there was no affair of confequence rela¬ 
ting to it, in which he was not either employed or con- 
fulted. His great merit, in this refpeCt, is fully proved 
by the various treatifes which he wrote on that fubjeCt; 
fuch as, II Ragionamento fopra la Campagna Pifana-; 
La Relatione fopra il modo de liberare la Campagna del 
Valdarno inferiore dall’inondazioni dall’ Ufciana; and 
Relazione della maniera di darefcolo alle acque ftagnante 
del pian del Lago ; which form a part of the ninth volume 
of the Raecolta of the author in regard to the motion of 
running water, published at Florence in 1774. It would 
be tedious to mention all the advantages which were the 
happy confequence of carrying Perelli’s ideas into execu¬ 
tion ; and which he explains in the works above men¬ 
tioned, and in others never publiilied. 
In the courfe of his different tours he collected remains 
of antiquity, and productions of the beft artifts; but par¬ 
ticularly painters, fculptors, and architects, of which he 
was an excellent judge ; alfo rare manuferipts and books. 
He 
