1434 (21 page)
Authors: Gavin Menzies
As far as I can see, every variation of shafts, wheels, and cranks “invented” and drawn by Taccola and Francesco is illustrated in the
Nung Shu
. This is epitomized in the horizontal water-powered turbine used in the blast furnace.
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This complex and sophisticated machine has a horizontal water-drive wheel to which is attached a drive belt. The drive belt powers a subsidiary shaft attached by a pulley to an eccentric crank linked by a crank joint and pushes (through rocking rollers and a piston rod) a fan bellows, which pumps air into the furnace. As Needham says: “We have here a conversion of rotary to longitudinal reciprocating motion in a heavy duty machine by the classical method
later characteristic of the steam engine, transmission of power taking place, however in the reverse direction. Thus the great historical significance of this mechanism lies in its morphological paternity of steam power.”
As far as I can determine, every type of powered transmission described by Taccola and di Giorgio is shown in the
Nung Shu
. There are several examples shown on the
1434
website.
In di Giorgio's column hoist
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the enmeshing gear wheels, right-angle gearing, pinwheel, and pin drum are employed.
In his illustration of carts with steering gear
22
(Codicetto
) he shows a crank arm fitted with connecting rods, and enmeshing gear wheels transform horizontal to vertical power.
A Chinese bucket pump.
So many of Taccola's ideas, including the bucket pump and waterwheel, are uncannily similar to the
Nung Shu
illustrations.
Taccola's drawings of reversible hoists
23
(
De ingeneis
) show flat teeth with enmeshing gear wheels transferring horizontal to vertical power,
together with a differential windlass and counterweight. Taccola shows the same.
The “vertical waterwheel with vanes”
24
illustrates vertical power being transferred to horizontal by enmeshing gear wheels, cranks and connecting rods, cam and cam followers, and right-angle gears.
Di Giorgio's chain pump activated by animal-powered horizontal wheel
25
has scoop wheels on spokes, eccentric lugs, bucket pumps, and continuous drive belts.
That di Giorgio plagiarized both Taccola and the
Nung Shu
is, in my opinion, supported by the following passage from Galluzzi:
A Chinese animal-powered chain pump.
Taccola's illustration of an animal-powered chain pump is strikingly similar to the Chinese version.
Beasts of burden made much better workers than humans for some jobs!
Santini's design mimics and then develops the process somewhat.
The vertical waterwheel is shown to have many applications in the
Nung Shu
.
A similar vertical waterwheel is found in Taccola's treatise on machines.
The four basic categories of Francesco's machines exhibit some interesting new features. First the inclusion of written commentaries enhances the
graphic representations of the devices with lexical information of major interest, data on materials and dimensions, special construction hints, and specific applications [the
Nung Shu
contains written commentaries]â¦. In some drawings of mills he introduces quantitative analysis on the relationships between teeth, wheel, and pinion diameters.
The author was clearly intent, however, on defining criteria to organise his materialâa concern virtually absent not only from Taccola's work and Francesco's early writings but also from all prior books about machines [the
Nung Shu
is organized by criteria]â¦.
The section on mills was most heavily expanded reaching 58 separate itemsâ¦. The chapter on pumps was similarly expanded in the
Trattato
I, which discusses a vast range of this kind of device. Conversely the section on carts and “pulling and lifting devices” was reducedâ¦. In particular the number of machines for lifting and moving columns and obelisks was drastically cut. The tendency to narrow the discussion to basic examples of each machine type gathered considerable momentum in the so called second draft of the work (
Trattato
II)â¦. Only ten illustrations of mills survived, but now they were strictly arranged by energy source: overshot bucket water wheel, horizontal paddle (a ritrecine) wheel, horizontal axis windmill, crank shaft (a frucatoio) mill with a flywheel bearing metal spheres, human-powered and animal powered mills (three designs with different transmission systems) and lastly the horse-powered tread wheel (two designs; one in which the animal moves the wheel from the inside, the other in which the animal applies pressure on the outer rim). [All these mills illustrated by Francesco appear in the
Nung Shu.
]
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Galluzzi continues:
The successive drafts of the
Trattato
therefore chart the evolution of Francesco's technological method from a potentially infinite series of exampla to the definition of a limited number of “types.” Each of these embodied the basic principles of a specific technical system which could then vary ad infinitum to suit the craftsman's needs. [As di Giorgio himself confirms in
Trattato
II:] “and with these we conclude the section on instruments for pulling weights in construction work, since from these one can easily derive the others.”
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