THE ENGLISH MILE : ITS RELATION TO 7HE EARTH. 89 
purely decimal, except that the Babylonians had the duodecimal mixed up in 
their system, with alternations of 6 and lo. 
To facilitate the view, the different results are arranged in the table in chrono- 
logical relation with prominent epochs, and in connection with the above lengths 
of stadia : 
Earth's Length 
circum- of stad. 
fereuce English 
Epoch, Event, etc. in stadia. feet. 
B. C. 538 Babylon taken by Cyrus. 
B. C. 525 Independence of Egypt destroyed by Cam- 
byses. 
B. C. 340 Aristotle 300,000 437.76 
B. C. 332 Macedonian Conquest; end of the Pharaohs. 
B. C. 250 Archimedes 300,000 437.76 
B. C. 230 Eratosthenes . . 250,000 525.312 
B. C. 146 Greece made a Roman province. 
B. C. 90 POSIDONIAS 240,000 547.20 
B. C. 30 Cleopatra's death; end of the Ptolemies; 
Egypt becomes a Roman province. 
A. D. 170 Ptolemy (in the reign of Marcus Aurelius) 180,000 729.60 
With these values of the stadium, the circumference in each case is 131,328,- 
000 English feet. 
By Clarke's elements of 1878, as quoted by Prof. Merriman, the mean cir- 
cumference is 131,331,455 English feet. 
The skill and accuracy of ancient astronomers is strikingly illustrated by the 
survey of Almamoun, in Mesopotamia, in the 9th century, referred to for illus- 
tration by both Prof. Merriman and M. Faye. Taking the Arabian mile (palpa- 
bly a version of Ezekiel's 500 reeds) at Haswell's quotation, 2,146 yards, with 
the Professor's statement of the result, 56^ miles to the degree, the circumfer- 
ence is 2,i46X3X56/^X36o=i3i>335>2oo feet, a trifle above the ancient and 
modern, in a total disagreement as to the whole circumference of less than a mile 
and a half. 
Both Egypt and Mesopotamia are fairly situated for apprehending the mean 
circumference by meridian observations. 
Leaving aside, for the moment, the above suggested adjustment of the royal 
cubit, the question arises pretty distinctly whether the most promising theory to 
square with all the facts may not, after all, be something like this : 
(i.) At the very earliest assignable epoch, the mean circumference of the 
earth, and consequently its radius, were known with astonishing precision. Un- 
der a very perfect system of geometry, the metrics of the ancient leading nations 
were founded on this knowledge. The opinions of Aristotle and Archimedes 
were derived from this source, through Egypt. 
(2.) After the Macedonian conquest, it became apparent that, by the break- 
ing up and commingling of nationalities, the multiplicity of units was inconven- 
