The Plan of St. Gall :: :: University of Virginia Library

There existed in the Middle Ages, as already mentioned,
yet another pounding mechanism making use of camming
action that cannot be overlooked in this context. It worked
with vertical pestles rather than with recumbent hammers.
Illustrations of these are found in the Mittelalterliche
Hausbuch of about 1480,[535] in several manuscripts of
Leonardo da Vinci[536] and in the manuscript attributed
to an anonymous Hussite engineer of around 1430 (fig.
456). Needham considers these vertical stamping mechanisms
"as characteristically European as the recumbent
tilt-hammer was Chinese."[537] This may be true, but there
is no historical assurance whatsoever that in Europe the
invention of the former preceded the adoption of the
latter[538] and any attempt to interpret the pilae of the Plan
of St. Gall, or the pistillos, sive malleos, vel certe pedes
ligneos of the thirteenth-century description of the water-powered
trip hammers of the Abbey of Clairvaux in the
light of this vertically operated pounding mechanism
would be straining the available historical evidence beyond
the limits of propriety. Amongst the vertical medieval
crushing devices listed by Needham, or anyone else
as far as I can see, there is not a single one with pestles
the shape of which could in any manner be compared
with that of a hammer (malleus) or a foot-shaped member
(vel certe pedes ligneos). A hammer, whether struck horizontally
or vertically, hits its object on impact, in a position
which places its longitudinal axis parallel to the surface
that receives its blow. It can accomplish this only with the

246

[ILLUSTRATION]

PLAN OF ST. GALL. MORTAR HOUSE. AUTHORS' INTERPRETATION

458.B

458.A

458.D

458.C

PLAN. TRANSVERSE SECTION, LONGITUDINAL SECTION; SOUTH ELEVATION

The Mortars of the Plan are here reconstructed as water-driven mechanisms, with their axle-trees oriented east and west and the presumptive
waterwheels to which these were geared oriented in the same direction, as are the waterwheels of the reconstructed Mill (above, fig. 448. A-E).

247

[ILLUSTRATION]

PLAN OF ST. GALL. AUTHORS' RECONSTRUCTION

458.E

458.F

WEST ELEVATION, NORTH ELEVATION

If a stream existed on the site and the land gradient permitted the development of waterpower, great efficiency could be achieved by this
alignment of the wheel races. For justification of water-powered mechanisms see above, p. 232, caption to fig. 448. In actual construction, we
believe such details would have been resolved by experienced craftsmen.

aid of a "foot-shaped" head piece lying at right angles to
its longitudinal axis. In the vertical crushing mechanism,
illustrated by the anonymous Hussite engineer (1472-78),
the Hausbuch Master (ca. 1480) and Leonardo da Vinci
(turn of the fifteenth to the sixteenth century), the pestles
are pointed, i.e., pencil-shaped, and could not by any
stretch of the imagination be interpreted as "hammer-" or
"foot-shaped" instruments. There is no doubt in my mind
that the pilae shown on the Plan of St. Gall must be interpreted
as recumbent hammers. They have the shape of
hammers, and the presence of a drum at the end, which
lies opposite the head of the hammer, as well as their
dimensions, allows for no other interpretation.[539]

[535]

Schmithals and Klemm, 1958, 4.

[536]

Das Mittelalterliche Hausbuch, fol. 36v. See Bossert and Storck
1912, pl. 40.

[537]

For detailed references to Leonardo's drawings of vertical crushing
mechanisms see Needham, op. cit., 395, note d.

[538]

It has been generally overlooked in this discussion that the same
anonymous Hussite engineer, who furnishes us with the earliest visual
representation of a vertical pestle stamp provides us also with an illustration
of a grain-crushing mechanism, operating with recumbent
hammers (Munich, National Bibliothek, Ms. lat., fol. 17v; see Beck,
op. cit. 278-80). I am drawing attention to this fact because there seems
to be a tendency, in the literature on this subject, to think that in Europe
the use of the vertical pestle stamp preceded that of mechanisms working
with recumbent hammers, because of the erroneous view that the former
is earlier attested in the visual arts. This would not only be a conclusion
highly questionable in itself, but also one based on mistaken facts. Both
instruments portrayed and described by the Hussite Engineer are hand-operated
and of rather light construction, made for home rather than
industrial use, and therefore not really comparable to the heavy equipment
shown on the Plan of St. Gall or described in the poetic thirteenth-century
account of the waterworks of Clairvaux.

The traditional date of Ms. Lat. 197, "ca. 1430" (Beck, 1899, 280;
Needham, IV:2, 1965, 395; Horn, Journal of Medieval History I, 1975,
244) must be revised. Lynn White informs us that Bert A. Hall, in an
unpublished dissertation "The so-called `Manuscript of the Hussite Wars
Engineer' and its Techological Milieu: A Study and Edition of Codex
Latinus 197, Part 1," University of California, Los Angeles, 1971) showed
conclusively that it is two manuscripts bound together. They are from
the hands of two engineers, neither of whom can be shown to have had
any involvement in the Hussite Wars. Folios 1-28 can be dated to ca.
1472-1485, folios 29-48 to ca. 1485-1496.

[539]