Measuring the Size of the Earth in Antiquity
Berlin · June 2001
Eratosthenes supposedly determined the size of the earth, and his calculations were not surpassed until 1800 years later. Even worse: According to historiographers Ptolemy's erroneous tablets and maps were imposed on the medieval world and only laid aside in the 16th century. Yet evidence suggests that these are fairytales just like other stories that are presented as history. Maps showing the real face of the earth always existed. They might be pre-catastrophic.
|Part I: Measures|
There exists a prehistorical pattern for geodetic purposes covering the
land on a great scale, as Walther Machalett and Hermann Zschweigert found
out during many years of research. The result of the trigonometric works
of the ancients has been preserved in many megalithic structures, from
the dolmens and cairns of France through Central European megaliths down
to Egyptian pyramids. Their measurements confirm the use of unified lengths
that are fractions of the earth's diameter or circumference.
To calculate the
diameter or the circumference of the globe two basic measurements are
needed: The distance between two localities - A and B - on a meridian
(same longitude), and the parallel (degree of latitude) of the two localities.
In school we learned
that Eratosthenes (276-194 B.C.), director of the great library at Alexandria,
was the first to determine the size of the earth. Yet his alleged method
does not convince me at all.
The latitudinal difference
between Alexandria and Syene, 7°12', is exactly a 50th part of the
whole circumference. If this had been applied correctly in the calculation,
the circumference would have come to 250,000 stades, or 2000 stades short
of what Eratosthenes assumed. This suggests he knew the outcome in advance
and only looked for measures that led to the right result.
|Part II: Greek science|
One of the great
German scholars at the end of the 19th century, Konrad Miller, worked
on the ancient geographers in Greek and Latin texts, and especially on
Eratosthenes. He says that "in the whole antiquity there is only
one single measurement of the earth worthy of that name, the one made
by Eratosthenes" (published 1919, p.16; my translation as in all
quotes that follow). According to Miller all other ancient geographers
such as Posidonius, Ptolemy etc. copied or misunderstood Eratosthenes'
|Part III: Maps|
The oecumene, that
is: the great landmass from the straits of Gibraltar (the Pillars of Hercules,
as they were known) to the end of southeast Asia (probably Korea), was
one of the important measures for ancient geographers. As it is extremely
difficult to determine the meridian (longitude) of a place, these measures
even in Renaissance time had been grossly wrong. According to Miller,
Eratosthenes gave 120° as the size of the oecumene, Posidonius 180°
. Harley and Woodward (p.156) allot 138° referring to the fragments
of Eratosthenes' Geographica transmitted in Strabo, a figure quite exact.
|Part IV: Arab tradition and Ptolemy|
Miller writes (chapter 3), that Eratosthenes' measurements were passed on to the Arabs, although they don't credit him but mention Hermes or Indians as authorities. Moreover the length of the measure used, the parasang, is never uniform. By different ways of transforming Arab data Miller arrives at the same results Eratosthenes had laid down, i.e., 252.000 stades for the circumference of the earth. Miller states that the Arabs did not understand their own writings although they measured from one latitudinal degree to the next in the Syrian desert. There are several reports of attempts to measure the distance of one latitudinal degree, especially from Alfraganus, but "unluckily none is authentic" (Miller, p. 33).
three different measurements of the degree and affirms that the result
agrees with that of Ptolemy, but Miller claims it is incorrect. Ibn Yunis
(officially died 1008, probably lived in the 14th century) also reports
very exact measuring work and the correct results, but says they were
not taken into account by contemporaries, because the ancient results
were generally used and could not be changed. Arab results for 1°
are only 1.5% to 2% wrong. Thus the circumference is between 39,168 and
39,400 km, very near to our data today. The deviation is again due to
not taking into account the exact meridian, a difficult task not resolved
until around 1600.
Another point on which we are badly informed is the assertion that in those times clerics thought that the earth is a disk. It is unclear why this rumor was invented, but all the dispute about the real size of the earth proves that at least everybody concerned knew the earth is a globe.
Next, Miller looks
at the world map of Ptolemy and realizes that the alleged measuring of
the coordinates of 330 localities - the "famous cities" - had
not been measured at all. Based on very few ancient dates Ptolemy built
up a system that was completely wrong and gave a distorted picture of
Miller goes on to
say that Ptolemy's great map was decisive all through medieval times in
an authoritarian way to such an extent that superior knowledge as contained
in itineraries and portolans (coastal maps for sailing) was not acknowledged.
A look at this model map reveals that coastlines and towns and rivers
and mountains are drawn at random and render it worthless. The Mediterranean
is stretched far too much; in reality it should only measure two thirds
the length Ptolemy gives. Rivers and landmarks in Northern Africa reflect
Roman standards of discoveries, which means they represent only those
parts of Morocco and Libya-Egypt that had been explored before that time.
|Part V: Renaissance|
Gregor Reisch (1503)
and Glareanus (1527) realized that Ptolemy's map was worthless but they
didn't know the reason. Only the Spaniard Jaime Ferrier explained the
mistakes as wrong renderings of the length of the stade when he handed
his note to Columbus in 1495 (printed in 1545; Miller p. 14)
|The radius and circumference
of the earth were known to megalith builders, and still available to Eratosthenes
who did not fully grasp the way they were attained but transmitted them
correctly, whereas later no scientist, not even the Arabs, made use of these
exact measurements. I can only imagine some obscure power that has changed
our knowledge of the past. We were told in school that Christian medieval
scholars believed in a disk-like earth although it is clear from all this
discussion that they knew shape and size of the globe very well. Who gained
by dumbfounding his people? And is he still at work?
Bachmann, Emil (1965): Wer hat Himmel und Erde gemessen? (Thun/Schweiz)
Addenda: I would like to add that I no longer believe in the authenticity and usefulness of the map of Piri Reis
of 1513, it might even be a falsification. (Topper 2017)
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