I
That the plant now commonly in use for pise-building is but a slight
improvement on the anciently accepted model, may be seen by a comparison
of modern examples with old engravings and descriptions. Pise-building
lay off the great main stream of constructional activity, and the
enterprise and ingenuity lavished on the perfecting of other building
materials and methods passed Pise by, leaving it undisturbed in its
quiet backwater, a primitive system still with its primitive tackle.
Yet there were a number of very obvious and unnecessary shortcomings in
the accepted shuttering that seemed to clamour for attention, defects,
too, that were in no way inherent, but merely traditional infelicities
reproduced in succeeding models that remained remarkably true to their
primitive ancestral architype--the Pise plant described by Pliny.
Here seemed to be a very promising field for an ingenious inventor,
a field that is still "To Let."
In the absence of any such inventive genius, the author has had certain
ideas of his own embodied in the "Mark V" type of shuttering--a type
that further experience and experiment will doubtless modify.
The principle of the building-process remains unaffected. The
improvements, such as they are, are merely improvements of mechanism.
[Illustration:
DIAGRAM OF MARK V PISE SHUTTERING]
[Illustration:
+Mark V Shuttering.+
Showing top cross-braces thrown back and free leg disengaged.]
[Illustration:
+Mark V Shuttering.+
Showing screw-up securing tackle of exterior corner-piece
and its rounded interior. Also screw-cramp at interior angle
of shuttering.]
[Illustration:
+Mark V Shuttering.+
Shuttering about to be removed from a first section of Pise walling.
Top cross-braces have been thrown back and clamps to legs released.
It is now only necessary to detach the stays and lift away the
shutters. Where, as here, there is no masonry plinth, the
bearing-pins are only required for the succeeding courses of Pise,
and need not be inserted for the first.]
[Illustration:
+Mark V Shuttering.+
The angle-iron stay with cross-brace raised, and the blocking-box
showing its internal clamping-gear.]
Scientific research could doubtless, if it would, do much towards
perfecting Pise-building.
We know very little about the behaviour of different earths under
compression, or of their several reactions to chemical treatment.
Meanwhile, a few trifling mechanical modifications are all that
distinguish our modern plant from that devised by the ancients. That
said, a short description of the "Mark V" model may be of some interest,
pending the future developments that may now be hoped for.