I 
440 ' 5 S 0 
fuppofed to -defcend with a uniform velocity, or without 
any acceleration. Leibnitz, in the Aft. Erud. Lipf. for 
April 1689, has a difcourfe on the Linea Ifochrona, in 
which he (hows that a heavy body, with the velocity ac¬ 
quired by its delcent from any height, may defcend from 
the fame point by an infinite number of ifochronal curves, 
which are all of the fame fpecies, differing from one ano- 
•ther only in the magnitude of their parameters, (.fuch as 
are all the quadrato-cubical paraboloids,) and confequently 
Similar to one another. He (hows alfo how to find a line, 
•in which.a heavy body, defcending, (hall recede uniformly 
from a given point, or approach uniformly to it. 
ISO.CO'LON, f. [from 10-0;, Gr. equal, and x.u\ov, a 
member.] A fpecies of compofition in which the two 
( members pr principal parts of a lentence are of an equal 
' length. 
ISOCRATES, a celebrated Greek rhetorician, was 
born at Athens about B. C. 436. His father was a maker 
of mufical inftruments, who gave him a good education, 
•but, being ruined in the Peloponneiian war, left him no 
other inheritance. He had (tudied under Gorgias, Pro- 
dicus, and othe'r great mafters of eloquence; but a weak 
voice and timid dilpofition prevented him from exercifing 
the talent of (peaking in public. He employed himfelf 
therefore in compofing difeourfes in his clofet, and in 
teaching the art of rhetoric. He firft opened a (chool at 
Chio, where one of his auditors vs'as Timotheus fon of 
Conon, whom he accompanied to feveral parts of Greece 
as his fecretary. He then taught at Athens, with a repu¬ 
tation which brought him numerous difciples and confi- 
derable emolument. Hie alfo obtained valuable recom- 
pences for fome of his writings, particularly a moral dif¬ 
courfe which he addreffed to Nicholas king of Cyprus, 
and was rewarded by a gratification of twenty talents (be¬ 
tween four and five thoufand pounds). Though he fome- 
times courted the great and powerful, he was capable of 
giving expreflion to free and generous fentiments. When 
Theramenes, prolcribed by the thirty tyrants, took refuge 
at the altar, he role to (peak in his defence, at the hazard 
of (haring his fate; and after the death of Socrates, when 
his difciples all took td flight, he dared to appear in 
mourning in the (treetsof Athens. It was his praife that 
he never by writing or accufation injured a Angle indi¬ 
vidual, whence he palled a long life in peace and honour. 
He had reached his ninety-eighth year at the fatal battle 
of Cheroncea, B.C. 338; when, unable to bear the cala¬ 
mity which had fallen on his country, he abftained from 
food during four days, and expired. The abbe Arnaud 
fays that he died a few days before that fatal battle. A 
ftatue of bronze was railed to his memory by Timotheus, 
and another ftatue by his adopted fon Aphareus. The 
ftyle of Ifocrates is pure, fweet, and flowing, fometimes 
pompous and magnificent, fometiines diffule, and over¬ 
loaded with ornament. He was extremely attentive to 
the harmony of his periods, and Cicero reckons him the 
firfl: who introduced into Greek prole that numeroiity and 
melody of which it is lo lufceptible. His eloquence was 
little adapted to popular affemblies or forenfic contefts,and 
rather aimed to gratify the ear than affeft the heart. He 
polifhed all his compofitions to excefs. His panegyric on 
Athens was faid to have coft him ten years’ labour. He 
fucceeded beft in moral topics, which he treated with 
many bappy terms and found maxims. He was a fkilful 
teacher of rhetoric, and brought up many able difciples. 
There remain of liberates twenty-one difeourfes, which 
have been diftributed into the moral, the deliberative, the 
panegyrical, and the agonfftical. There are alfo nine 
epiffles bearing his name. Of the editions-of the works 
of Ifocrates, the principal are thofe of Aldus, 1513 and 
3 5 34-; of H. Stephanus, 1593, folio; of Wolfius, Paris, 
1621 ; of Battie, Carnbr. 1729, and Lond. 1749 > and of 
Auger, Paris, 1782. The latter editor has publilhed a 
complete French tranflnticn of this author. Moreri. Monthly 
Mag. De c. 1805. 
JLSOE'TES,^. [from »cro? 3 Gr. like, and tro;, year; be- 
I s o 
ing alike, or evergreen, all the year.] Quillwort; in 
botany, a genus of the clafs cryptogamia, in the order 
filices, or mifcellanese, and natural order of filices, or ferns. 
The generic characters are—I. Male flowers folitary within 
the bafe ot the inner leaves. Calyx: lcale cordate, acute, 
feflile. Corolla: none. Stamina: filaments none; an- 
therae roundifli, one-celled. H. Female flowers folitary, 
within the bale of the outer leaves of the fame plant.. 
Calyx: as in the males. Corolla: none. Piftillum : germ 
ovate, within the leaf. Pericarpium : capfule fubovate, 
two-celled, concealed within the bafe of the leaf. Seeds: 
numerous, globular. Fruftification immerfed in the di¬ 
lated bafe of the leaves, on the outfide like a capfule with 
a (treak refembling a future, but without any partition on 
the infide; filled with many granular feeds.— EJJ'ential Cha- 
raSler. Male : antherse within the bafe of the tond. Fe¬ 
male : capfule two-celled, within the bafe of the frond'. 
Species. 1. Ifoetes lacuftris, or common quillwort: 
leaves awl-lhaped, #emicylindrical, curved hack. Root 
fibrous; fibres numerous, fimple, (lender, linking deep 
into the mud. Leaves in thick tufts, eight or ten, from 
three or four to fix or leven inches in length, extremely 
like young ruihes, convex on the back, fiat or (lightly 
convex in front, at the bafe fwelling into a kind of bulb, 
covered by a thin tender (kin, which burfts and difeovers 
itfelf to be filled with numerous minute whitifti feeds, 
that appear fpherical when examined in the microfcope, 
roughifli, fomewhat tranfparent, and having three ribs 
meeting in a centre. See the Iris Plate, tig. 3. The 
leaves are fo brittle, that they break on the lead attempt 
to bend them. Each leaf conlifts of feveral (lender tubes, 
imbedded in a foft fpongy (ubltance, and furnilhed with 
tranfverfe diaphragms that are very vifible. When newly 
taken out of the water, it is pellucid. The edges of the 
inflated bafe of the outer leaves, where the female flowers 
refide, form a thin fine membrane, which fo clolely em¬ 
braces the gibbous part of the inner leaf, where the male 
flower is found, as to exclude the water. And by this 
admirable contrivance, the flowers of each fex are not only 
near each other, but, though at the bottom of a lake, are 
kept perfeftly dry. After the difeharge of the feeds, the 
outer leaves fall off and perifh, and the next in order per¬ 
form the lame office a fucceeding year; and the number 
ot leaves is kept up by a fupply of young ones from the 
centre. • Native of mountain-lakes, in the north of Eu¬ 
rope ; Weftmoreland ; Cumberland; Wales and Scotland ; 
flowering from May to September. 
2. Itoetes Coromandeliana, or Coromandel quillwort: 
leaves filiform, ereft, fmooth. This relembles the pre¬ 
ceding very much, but is larger. The leaves are near a 
foot long, filiform, not femicylindric. Native of Coro¬ 
mandel, in wet places that are inundated in rainy leafon. 
ISO'LA, a town of Naples, in Calabria Ultra, the fee of 
a bilhop, fuftragan of St. Severina : fifteen miles louth- 
eaft of St. Severina. Lat. 39. 2. N. Ion. 17. 24. E. 
ISO'LA, a town of Naples, in the province of Lavora, 
on a (mall ifland in the Garigliano: five miles Couth of Sora. 
ISO'LA, a town of Iftria, built on an ifthmus which 
extends a conliderable diftance into the fea. The envi¬ 
rons are celebrated forRibolla wine: feven miles fouth of 
Capo d’Utria. Lat. 45. 37. N. Ion. 13.40. E. 
ISO'LA, a river which rifes in the mountains of Tyrol, 
and runs into the Drave near Lientz. 
ISO'LA AL'TA, a town of Italy, in the department of 
the Mincio : eleven miles north-north-eaft of Mantua. 
ISO'LA de DOVARE'SI, a town of Italy, in the de¬ 
partment of the Upper Po, on the Oglio: twelve miles 
north-eaft of Cremona. 
ISO'LA della FEMI'NE, a fmall ifland near the 
welt coalt of Sicily, formerly a place of baniftiment for 
women. 
ISO'LA GROS'SA. See Grossa, vol. ix. p. 36. 
ISO'LA POCCARIZ'ZA, a town of Italy, in the de¬ 
partment of the Mincio; eighteen miles nortfi-eaff of 
Mantua. . 
3 ISO'LA, 
