V.7.1
THE CENTRAL HEARTH AND THE
LOUVER
THE MEANING OF LOCUS FOCI AND TESTU
One of the striking typological characteristics of the guest
and service buildings on the Plan is the squares in the
center of these houses referred to varyingly as locus foci and
testu (fig. 358A-C). The first of these terms clearly refers
to the "fireplace" or open hearth in the middle of the floor
which heats the house. The second, testu, requires some
explanation. It has generally been taken to be an abbreviation
for the word testudo ("turtle" or "roof"),[226]
but I do
not think that this is the correct interpretation. Testu, as an
abbreviation for testudo, with no sign given to indicate that
a part of the word is missing, is not consistent with the
author's other abbreviations,[227]
and there is no reason to
assume that he departed from his normal procedure because
of the smallness of the space in which the word had
to be inscribed. The testu square in the Hospice for Pilgrims
and Paupers (fig. 358B) is large enough to accommodate
the whole word testudo and several other words if
necessary. What the scribe had in mind, in my opinion, was
the word testu, exactly as it is written—a rare yet perfectly
meaningful term.
Testu (indeclinable) means the "lid of a pot."[228]
It is
closely related to testa, which means "shell," either the
shell that covers a testaceous animal, the human skull
(testa hominis), or human artifacts of comparable construction,
such as clay bowls or pots.
Testudo is a derivative of
both these words. It shares with them the basic meaning
of "protective cover." In everyday language
testudo meant a
"tortoise" or "turtle"; in military language it was the name
for the protective covering formed when soldiers held their
shields overhead and locked them together. By analogy, in
architectural terminology—both classical and medieval—
testudo came to be the word used for "roof," usually a roof
of timber, but also by extension, a "vaulted roof."
[229]
Even supposing that the author of the Plan had in mind
testudo, rather than testu, it is unlikely that he referred to
the principal roof of the building; rather, he must have
meant a roof equal in size with the square in which
the term was written; and since this square is designated
both as testu and as locus foci, it is most probably to be understood
as "a protective shield above the hearth," the purpose
of which must have been to form a cover for a central smoke
outlet. Such openings in the roof above the hearth are, in
fact, a feature of the protohistoric and early medieval building
tradition just discussed, and they remained an intrinsic
part of vernacular buildings throughout the Middle Ages.
THE LIGHT AND SMOKE HOLES OF THE
NORDIC SAGA HOUSE
This roof device is well attested in the Nordic Sagas where,
according to its function, it is referred to varyingly as
"smoke hole" (reykháfr, reykberi), "light inlet" (ljóri), or
"air inlet" (vindgluggr, vindauga).[230]
Little is known about
the size and shape of these devices, but apparently they
were large enough to be used as an escape hatch when all
other passages were blocked. The Sagas abound with tales
of exits made in this manner. A passage from the Vatnsdœla
Saga gives a typical example: "And so was this [house]
arranged that from that pile of goods, one could step up
into a big smoke hole [í einn storan reykbera] which was
over the hall [er á var skálanum] and when the marauder
investigated the pile, þorsteinn was outside" [var þorsteinn
úti, the sense being: þorsteinn had gained his freedom by
escaping through the smoke hole].[231]
The openings of these light and smoke holes could be
closed by means of wooden shutters (spjaeld) or boards
(fjöl) which were placed in position with the help of a pole
or rope; or they were screened with transparent membranes
made from the stomach lining of a hog mounted on movable
frames (
skjágluggr, skjávindauga). We read of the first type
in
Haralds saga harđrađa: "The king then let a board
(
fjöl) be moved in front of the light hole (
ljórann) so that
only a small opening was left . . . Einar entered and said,
`Dark is it in the King's Council Hall (
málstofa).' At the
same moment men rushed on him. . . ."
[232]
The second type is
mentioned in an equally dramatic passage of the
GullÞoris
saga, where Þorir, finding himself trapped in the hall
by Þorbjörn's housecarls, with all exits blocked, "grabbed
a pole and raised it under the `skin hole' (
skjárinn) and
there went out and pulled up the pole, and then ran up to
the mountains."
[233]
PROTOHISTORIC EVIDENCE FOR
LIGHT AND SMOKE HOLES
Evidence for the existence of poles rising from the ground
to form a canopy around and over the hearth has been
found in aisled Iron Age houses at Hodorf, Germany (fig.
307), and Wijchen, Holland (fig. 359), as well as in the
Migration Period houses of Nauen, Germany; also in
single-span Iron Age houses at Kraghede, Vendsyssel,
Denmark (fig. 360); Källberga, Alunda (Uppland), Sweden;
and the Migration Period village Vallhagar on the island
of Gotland, Sweden.[234]
The relatively rare occurrence of these hearth poles
suggests, however, that in general the protective shields
were mounted directly on the roof rather than on special
supports. The latter system would have been entirely inappropriate
in larger halls, since it would have required an
underpinning of timbers entirely out of scale with the
superstructure that it served to support.
MEDIEVAL EXAMPLES
A fairly accurate picture of these smoke and air hole
coverings may be obtained from some of the old engravings
of early English college halls, for instance, those of Oxford's
New College (fig. 361) and Magdalen College (fig. 362), as
shown in David Loggan's illustratious Oxonia Illustrata of
1675.[235]
New College Hall, the oldest of the surviving college
halls of Oxford, was built between 1378-1386 by William
of Wykeham. Magdalen College was founded in 1448 by
William of Waynflete, but its buildings were not completed
until 1480. Both these halls were built during a period when
new discoveries in the technique of roof construction made
it possible to dispense with the two rows of roof-supporting
posts which formerly divided the hall into a nave and two
accompanying aisles. Thus it became possible not only to
cover the space in a single span but also to lift the roof upon
walls of considerable height. Yet even in this new and more
fashionable hall, which permitted large windows, the traditional
opening in the roof above the hearth was retained
as the principal exit for smoke. The roof of the hall of
Magdalen College shows what extraordinary dimensions
these openings could obtain.
The medieval term for these smoke holes is fumerium
("smoke hole") or lovarium (identical with Old French
louvert, "opening"). The so-called Liberate Rolls of King
Henry III, issued in 1216 and 1272 (verbal directive for
repair and construction of houses owned by the crown)
make frequent reference to these devices.[236]
Loggan's engravings
of the halls of New College and Magdalen College
show how these smoke holes were covered by a simple
saddle roof, which looks like a portion of the main roof cut
out and raised over the hole. In Loggan's Oxonia Illustrata
saddle-like louvers appear only on the roofs of the earlier
college halls. On the roofs of the later halls the saddle-like
louver was replaced by a flèche or lantern, a Gothic development
and one which the author of the Plan of St. Gall
is not likely to have envisaged.[237]
The saddle-like version is the simpler and, unquestionably,
the older form, and this type of fumerium is in my
opinion what the author of the Plan had in mind when he
used the term testu.
MODERN SURVIVAL FORMS
Superstructures of this type, almost extinct in the Old
World, are a common feature of the timbered barns in the
great farm belt of the United States (fig. 363). This device
was brought over by early settlers, along with the very type
of building for which it had been invented in the Early
Iron Age. Hundreds of thousands, if not millions, of aisled
American hay and dairy barns of timber are ventilated even
today by openings in the roof ridge, which are shielded by
elevated sections of the main roof and which still retain the
shape of what in the Middle Ages was probably the most
common means of controlling light and smoke.
The design of such a device from a barn in the vicinity
of Benicia, California (fig. 364), is probably as good a guide
for the reconstruction of the louvers of the guest and service
buildings on the Plan of St. Gall as any equivalent found in
Europe, where this particular device disappeared rapidly in
residential architecture once the open fire was replaced by
hooded chimneys, a development that must have been
nearly complete by the beginning of the fifteenth century.
Despite a thorough search among Flemish, Dutch, and
German landscape drawings, etchings, and paintings—
media which have richly and vividly preserved the architectural
panorama of the medieval countryside—I have
been able to trace only a single case of survival in post-medieval
architecture, and a belated one at that. In an ink
drawing of 1770 by Jean le Prince, entitled Les Lavandières
(fig. 365) there is shown in the center of the bridge that
crosses a stream an old rectangular house with an opening
in the ridge which is shielded by a raised portion of the
main roof above the spot where in the period of construction
of this house there must have burned an open fire.
Together with the saddle-shaped superstructures over the
ridge of the halls of New College and Magdalen College at
Oxford, this drawing of Jean le Prince may retain the most
truthful visual record of the device which in the guest and
service buildings of the Plan is referred to as testu.
HINGED HATCHES
However, in the Lowlands during the sixteenth century,
there existed a related device which, judging from the frequency
of its appearance in the illuminations of the Grimani
Breviary and other Franco-Flemish manuscripts of the
same period, must also have been a common feature in late
medieval house construction. A considerable number of
houses represented in the landscapes of these manuscripts
have smoke holes covered by wooden hatches hinged to the
ridge, which could be raised or lowered by means of pulleys.
This device appears in three different places in the Grimani
Breviary: the July representation (fig. 366), the March
representation, and the well-known February representation
(fig. 367), in which a wisp of smoke can be distinguished
rising in gentle spirals into the chilly winter air from an
open fire burning directly below the smoke hole on the
simple clay floor.[238]
Again, it is depicted in the September
representations of the breviary of the Museum Mayer van
den Bergh at Antwerp[239]
and in an illustration, which depicts
the lying together of Ruth and Boaz, from a Dutch Bible
illuminated around 1465 (fig. 368).
[240]
The technical details
of how such roof flaps were operated are well explained in
the sketches of a vent of a Frisian farmhouse of the eighteenth
century, published by K. Uilkema (figs. 369 and
370).
[241]
A wooden hatch or lid of this kind would be in complete
accord with the term testu ("lid"), but the dimensions of
many of the testu squares of the Plan of St. Gall, some of
which are as large as 10 feet square (Hospice of the Paupers,
House for Distinguished Guests), speak against this being
the type used. Hinged lids of such dimensions would be
unmanageable. The saddler roof is the simple and the earlier
form, and for this reason in our reconstruction of the guest
and service buildings on the Plan, we have chosen the latter
version.
