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* Eratosthenes ( 276194 BC ), who made the first known reliable estimation of the Earth's size.

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## Some Related Sentences

Eratosthenes and BC

As noted in

**the**book Huai Nan Zu, in**the**2nd Century__BC__Chinese astronomers effectively inverted__Eratosthenes__' calculation**of****the**curvature**of****the**Earth to calculate**the**height**of****the**sun above**the**earth**.**
Maps based on scientific principles had been

**made**since**the**time**of**__Eratosthenes__**(**3rd century__BC__**),**but Ptolemy improved projections**.**
Those

**who**believe that**the**stories**of****the**Trojan War are derived from a specific historical conflict usually date it to**the**12th or 11th centuries__BC__, often preferring**the**dates given by__Eratosthenes__, 1194 – 1184__BC__, which roughly corresponds with archaeological evidence**of**a catastrophic burning**of**Troy VIIa**.**
Ephorus gives 1135

__BC__, Sosibius 1172__BC__,__Eratosthenes__1184__BC__/ 1183__BC__, Timaeus 1193__BC__,**the**Parian marble 1209__BC__/ 1208__BC__, Dicaearchus 1212__BC__, Herodotus around 1250__BC__, Eretes 1291__BC__, while Douris 1334__BC__**.**
Ancient Greek historians variously placed

**the**Trojan War in**the**12th, 13th, or 14th centuries__BC__:__Eratosthenes__to 1184__BC__, Herodotus to 1250__BC__, Duris**of**Samos to 1334__BC__**.**

Eratosthenes and ),

Several works among

**the**best**known**during this long period could be cited as an example, from Strabo**(**Geography__),____Eratosthenes__**(**Geography ) or Dionisio Periegetes**(**Periegesis Oiceumene ) in**the**Ancient Age to**the**Alexander von Humboldt**(**Cosmos ) in**the**century XIX, in which geography is regarded as a physical and natural science,**of**course, through**the**work Summa de Geografía**of**Martín Fernández de Enciso from**the**early sixteenth century, which is indicated for**the****first**time**the**New World**.**
The Hellenistic world view after Seleucus: ancient world map

**of**__Eratosthenes__**(**276 – 194**BC**__),__incorporating information from**the**campaigns**of**Alexander and his successors**.**
Most ancient Greek and Roman chroniclers, poets, grammarians and scholars

**(**__Eratosthenes__, Varro, Apollodorus**of**Athens, Ovid, Censorinus, Catullus, and Castor**of**Rhodes ) believed in a threefold division**of**history: ádelon**(**obscure__),__mythikón**(**mythical ) and historikón**(**historical ) periods**.**
The two towns were separated by one degree on

**the**meridian, so from his measurement he was able to calculate a value for**the**circumference**of****the**earth – a feat celebrated in**the**title**of**his book__Eratosthenes__Batavus**(**The Dutch__Eratosthenes____),__published in 1617**.**
Herodotus, Strabo, and other classical authors repeatedly mention

**the**Caspians but do not seem to know much about them ; they are grouped with other inhabitants**of****the**southern shore**of****the**Caspian Sea, like**the**Amardi, Anariacae, Cadusii, Albani**(**see below__),__and Vitii**(**__Eratosthenes__apud Strabo, 11**.**8**.**8__),__and their land**(**Caspiane ) is said to be part**of**Albania**(**Theophanes Mytilenaeus apud Strabo, 11**.**4**.**5 ).
He had a high reputation as a Grecian, a Latinist and a philologist, and he brought out with

**the**collaboration**of**others his an edition**of**St Cyprian in 1682, an English translation**of**The Unity**of****the**Church in 1681, editions**of**Nemesius**of**Emesa**(**1671__),__**of**Aratus and**of**__Eratosthenes__**(**1672__),__Theocritus**(**1676__),__Alcinous on Plato**(**1677__),__St Clement's Epistles to**the**Corinthians**(**1677__),__Athenagoras**(**1682__),__Clemens Alexandrinus**(**1683__),__Theophilus**of**Antioch**(**1684__),__Grammatica rationis sive institutiones logicae**(**1673 and 1685__),__and a critical edition**of****the**New Testament in 1675**.**
Strabo in his Geography

**(**c**.**30__),__Book I, Chapter 4, mentions Thule in describing__Eratosthenes__' calculation**of**"**the**breadth**of****the**inhabited world " and notes that Pytheas says it " is a six days ' sail north**of**Britain, and is near**the**frozen sea**.*******Chronicle

**(**Χρονικά

__),__a Greek history in verse from

**the**fall

**of**Troy in

**the**12th century

**BC**to roughly 143

**BC**

**(**although later it was extended as far as 109

**BC**

__),__and based on previous works by

__Eratosthenes__

**of**Cyrene

**.**

:" Accordingly,

**the**Volcae Tectosages, seized on those parts**of**Germany which are**the**most fruitful lie around**the**Hercynian forest,**(**which, I perceive, was**known**by report to__Eratosthenes__and some other Greeks, and which they call Orcynia__),__and settled there**.**
By solving

**the**riddle**(**calculating all**the**prime numbers below 100 using**the**Sieve**of**__Eratosthenes__and pressing**the**corresponding buttons backwards__),__Roland and his ka-tet are allowed to board Blaine and flee Lud, just as Blaine releases poison gas**(**DEP3, a substance similar to what appears as a poison in another**of**King's books, Eyes**of****the**Dragon**.**

Eratosthenes and who

Although Strabo cited

**the**antique Greek astronomers__Eratosthenes__and Hipparchus, acknowledging their astronomical and mathematical efforts towards geography, he claimed that a descriptive approach was more practical, such that his works were designed for statesmen__who__were more anthropologically than numerically concerned with**the**character**of**countries and regions**.**__Eratosthenes__

**of**Alexandria,

__who__died about 194

**BC**, wrote on astronomy and geography, but his work is

**known**mainly from later summaries

**.**

Those

__who__believe that**the**stories**of****the**Trojan War derive from a specific historical conflict usually date it to**the**twelfth or eleventh centuries**BC**, often preferring**the**dates given by__Eratosthenes__, 1194 – 1184**BC**, which roughly correspond with archaeological evidence**of**a catastrophic burning**of**Troy VIIa**.**
Posidonius was informed in his approach to finding

**the****Earth's**circumference by__Eratosthenes__,__who__a century earlier used**the**elevation**of****the**sun at different latitudes to arrive at a figure**of**250, 000 stadia**(**which he rounded to 252, 000 so that it would be divisible by 60 ).
1241 indicates that Apollonius was succeeded in

**the**position by__Eratosthenes__; this must have been after 247 / 246 BCE,**the**date**of****the**accession**of**Ptolemy III Euergetes,__who__was probably tutored by Apollonius and__who__appointed__Eratosthenes__**.**
Lysias and Polemarchus were rich men, having inherited property from their father, Cephalus ; and Lysias claims that, though merely resident aliens, they discharged public services with a liberality which shamed many

**of**those__who__enjoyed**the**franchise**(**Against__Eratosthenes__xii**.**20 ).
Richard Pankhurst and others have argued that

**the**name should be understood as " River**of****the**Boras people ", where asta can be related to Proto-Nubian asti " water "., while-boras can be linked to a number**of**Roman allusions to a tribe named**the**Bora,__who__lived near Meroe, and another tribe named**the**Megabares**(**in__Eratosthenes__and Strabo, in Pliny**the**Elder ).__Eratosthenes__

**of**Alexandria,

__who__died about 194

**BC**, wrote on astronomy and geography, but his work is

**known**mainly from later summaries

**.**

About 150 years after

**the**disaster,**the**philosopher__Eratosthenes__visited**the**site and reported that a standing bronze statue**of**Poseidon was submerged in a " poros ", " holding in one hand a hippocamp ", where it posed a hazard to those__who__fished with nets**.**__Eratosthenes__,

__who__lived in Athens as a young man, claimed that Aristo and Arcesilaus were

**the**two most important philosophers

**of**his age

**.**

Eratosthenes and made

That alternative route, different from

**the**theoretical eastward route, was based on calculations**of****the****Earth's**circumference__made__by Columbus which showed**the**measurement to be substantially less than**the**classic 10, 000 mile figure given by__Eratosthenes__in**the**3rd century**BC****.*******The

**first**good measurement

**of**

**the**distance between Earth and

**the**Sun is

__made__by

__Eratosthenes__

**(**approximate date ).

The land that became

**known**as Khorasan in geography**of**__Eratosthenes__was recognized as Ariana at that time, which__made__up Greater Iran or**the**land where Zoroastrianism was**the**dominant religion**.**

Eratosthenes and first

__Eratosthenes__

**the**Cyrene was

**the**

__first__to divide

**the**surface

**of**

**the**earth into lines

**of**latitude and longitude

**.**

The Return

**of****the**Heracleidae, which is**the**closest event to a Dorian Invasion available in legend, must coincide with**the**entry**of**Aristodemus and his brethren into Arcadia, which, based on**the**chronology**of**__Eratosthenes__, happened 328 years before**the**generally accepted date**of****the**__first__year**of****the**__first__Olympiad, 776**BC****.**
The Return

**of****the**Heracleidae, which is**the**closest event to a Dorian Invasion available in legend, must coincide with**the**entry**of**Aristodemus and his brethren into Arcadia, which, based on**the**chronology**of**__Eratosthenes__, happened 328 years before**the**generally accepted date**of****the**__first__year**of****the**__first__Olympiad, 776**BC****.**
De Astronomia was

__first__published, with accompanying figures, by Erhard Ratdolt in Venice, 1482, under**the**title Clarissimi uiri Hyginii Poeticon astronomicon opus utilissimum This " Poetic astronomy by**the**most renowned Hyginus, a most useful work ," chiefly tells us**the**myths connected with**the**constellations, in versions that are chiefly based on Catasterismi, a work that was traditionally attributed to__Eratosthenes__**.**
Many parts

**of**modern geometry are based on**the**work**of**Euclid, while__Eratosthenes__was one**of****the**__first__scientific geographers, calculating**the**circumference**of****the**earth and conceiving**the**__first__maps based on scientific principles**.**
The

__first__**known**grade measurement was performed by__Eratosthenes__**(**240**BC**) between Alexandria and Syene in what is now Egypt, determining**the**radius**of****the**Earth with remarkable correctness**.**__Eratosthenes__was

**the**

__first__to write on physical geography ; he also

__first__attempted to draw up a chronological table

**of**

**the**Egyptian kings and

**of**

**the**historical events

**of**Greece

**.**

The founder

**of****the**mathematical school was**the**celebrated Euclid ; among its scholars were Archimedes ; Apollonius**of**Perga, author**of**a treatise on Conic Sections ;__Eratosthenes__, to whom we owe**the**__first__measurement**of****the**earth ; and Hipparchus,**the**founder**of****the**epicyclical theory**of****the**heavens, afterwards called**the**Ptolemaic system, from its most famous expositor, Claudius Ptolemy**.**0.112 seconds.