%
%    Holmes' commentary on Caesar's De Bello Gallico.
%    Discovery of Earthworks (preface 5).
%
%    Contributor: Konrad Schroder  <perseant@u.washington.edu>
%
%    Original publication data:
%         Holmes, T. Rice.  _C._Iuli_Caesaris_Comantarii_Rerum_in_
%                   _Gallia_Gestarum_VII_A._Hirti_Commentarius_VIII._
%                             Oxford: Oxford University Press, 1914.
%
%    Version: 0.01 (Alpha), 7 April 1993
%
%    This file is in the Public Domain.
%
\input ks_macros.tex
\centerline{HOW SOME OF CAESAR'S CAMPS AND}
\centerline{OTHER EARTHWORKS HAVE}
\centerline{BEEN DISCOVERED}
\bigskip
T{\sc HE} late Colonel Stoffel contributed much to our knowledge of the
history of the Gallic war by excavations, which he carried out on behalf of
Napoleon~III.  In 1899 he described to me his method in a letter which I
have printed in {\it Caesar's Conquest of Gaul} (1899, pages xvi--xxx;
1911, pages xxiv--xxvii), and of part of which I here give a free
translation.  This method was identical with that which is followed by
Professor Haverfield and other well-known investigators.

The colonel begins by remarking that land on which an entrenched camp can
be constructed always has an upper layer of productive soil ({\it terre
v\'eg\'etale}), varying from one or two to five feet thick, below which
lies the subsoil ({\it sous-sol} or {\it sol vierge}),---marl, limestone,
or other, according to the locality.  `When,' he continues, `after a battle
or a siege, the Roman army quitted its camp, the people of the country
would demolish the entrenchments, in order to be able to resume
cultivation; and they shovelled the earth of which the rampart was composed
into the ditch ({\it fosse}).  The ditch was thus filled with mixed soil,
composed partly of productive soil, partly of subsoil, and often containing
objects which the soldiers bad left on the rampart, such as broken weapons,
sling-bullets, coins, bones, \&c.  For some time the upper part of the
ditch which had been so filled up presented the [slightly convex] form {\sc
A~B} because the earth which had been thrown in did not pack closely; but
in course of time and owing to yearly cultivation, the ground settled down
to the level of the surrounding land; and thus all apparent traces of
Caesar's camps have disappeared.  The earth with which the ditches are
filled is loose and never recovers the consistency of virgin soil, so that
even now, after the lapse of 2,000 years, it easily breaks under the blows
of the pick.  This is what enables one to discover the ditches, when one
knows how to determine the probable position of a camp.  That, as you very
truly say, is the essential condition.  First of all, then, one must study
the country where one supposes the camp to have been situated; and to do
this requires a thorough knowledge of Caesar's Commentaries and also
special military knowledge.' I may remark that the camp would be
constructed, if possible, on an easily accessible and yet defensible
position, that is, on gently sloping ground: it would have to be near
pasturage for the horses, running water, and timber, which was needed both
for fortification and for firewood.

`The following', continues Colonel Stoffel, `is the method which I have
always adopted in order to discover the ditches of a camp.  Let {\sc
A~B~C~D} represent an area within which I believed that the camp of which I
was in search was to be found; and let us assume that the layer of
productive soil is 70 centimetres [about 2 feet 3$ 1\over 2$ inches] thick.

I placed the workmen, with their picks and shovels, in several rows {\it
fff~.~.~.}, at right angles to one of the supposed sides of the camp.  Each
of them had to turn up the layer of productive soil along a space two feet
wide.  If, after turning up the layer to a depth of 70 centimetres, they
felt their picks strike unyielding ground, that showed that the ground had
never been disturbed and that they were not on the Roman ditch.  The
workmen then continued to move forward.  But when they unmistakably reached
the ditch at {\it x~y}, the case was different.  Then, after turning up the
soil to the depth of 70 centimetres, they no longer found themselves, as
before, on unyielding ground: on the contrary, they met with loose soil,
which broke easily,---a sign that it had formerly been disturbed.  I then
enlarged the ``trench'' ({\it tranch\'ee})--the space that was to be
excavated-- giving it a width of six feet ({\it c~d}) instead of two ({\it
x~y}, to enable the men to work more easily; and they dug out the
``trench'' till they came to the bedrock.  One could soon tell, for another
reason, whether one was on the Roman ditch or not; for, if one was really
there, one could make out without difficulty on the two edges, {\it e~c}
and {\it f~d}, of the ``trench'' the outline of the ditch, which was
recognizable by the colour of the mixed earth---that of the old rampart---
contrasted with the colour of the virgin soil that surrounded it.

`I have never seen anything more curious than the outlines of the little
ditches of the small camp which I discovered on the hill of the
Roche-Blanche [at Gergovia (see p.~305)].  There the layer of productive
soil, at the most 50 or 60 centimetres thick (if my memory is good), lies
upon a calcareous subsoil as hard and white as chalk: the ditches of the
camp, filled with a mixture of productive soil and chalk, presented
outlines which stood out against the earth by which they were surrounded,
as sharply as the annexed triangle {\sc A~B~C}, on the white paper.'
\bye