THE ENGLISH MILE: ITS RELATION TO THE EARTH. 87 
lasted for seven, and then rotted, while creosoted specimens were as good at the 
end of twelve years as at first.^^ As a general process, Bethell's, including its 
21 Dingl. Pol. Jour., 123, 146, 1852. 
variations seems to be the best of all. — Proceedings Ohio Mechanics' Institute. 
ENGINEERING. 
THE ENGLISH MILE : ITS RELATION TO THE SIZE OF THE 
EARTH. 
JACOB M. CLARK, C. E. 
This itinerary, on account of its lack of geographical correlation, and singu- 
lar dimension, has evoked much interesting discussion, and been the means of 
bringing to the surface, under new aspects, a variety of important facts. 
The reader is referred to a very instructive article in Vol. 25, p. 69, of this 
magazine, giving a full abstract of the views of M. Faye, as read before the Paris 
Academy, "On the Origin of the English Mile." 
In that paper, the writer favors the view that the dimension is traceable to 
the survey of Eratosthenes, compared with that of Ptolemy; and, incidentally, 
that the surveys were conducted in terms of the Babylonian degree, and by im- 
pUcation, for the purpose of determining its length, or rather the subtense of one 
minute of arc ; that the error in dimension arose partly from misapprehending the 
relative values of the stadia of different epochs, through disregarding the assump- 
tion that the computation of Eratosthenes was based on surveys made with the 
Egyptian foot^ (0.27m. ^= 10^ inches), while the survey of Ptolemy was based 
on the Philetgerian foot (nearly 0.36 m. = 143^ inches). 
Much additional light is thrown on the subject through a valuable contribution 
to these pages, from the pen of Prof. Mansfield Merriman (" The Shape and Size 
of the Earth," Van Nostrand's Magazine, Vol. 22, p, 53-62, 115-128, and 233- 
241). Reference is more particularly made to the different versions of the earth's 
circumference by ancient mathematicians on page 58. In the absence of direct 
evidence to the contrary, the results, the definition of amplitude observed by 
Eratosthenes, and the chronology, ^ as given by Prof. Merriman, must be taken 
as clear and conclusive. 
1. The Egyptian foot is uncertain. The dimension above given agrees very fairly with the 
ady of Malabar, the palmo of Malta, Messina, Naples, Sardinia, and Nice, the pied of Rouen, 
the stonecutter's schuh of Zug, and the miner's spanne of Prussia ; dimensions varying from 
10.265 to 10.670 inches. 
The Philetseric foot is quoted by Alexander as equivalent to 13.893 inches. 
2. In a recent discussion (Trans. Am. Soc. U. E., Vol. XI, p. 415), the writer, adopting this 
chronology, inadvertently placed Aristotle 200, instead of 100, years earlier than Archimedes. 
