Voynich and Padua | The Water-Conduit Problem

The tubes in the Voynich Manuscript are visually persuasive.

They look like pipes.

Some look like conduits.

Some seem to connect pools.

That makes a hydraulic interpretation almost automatic.

Laubach 1425 gives us exactly the control needed to slow that inference down.

Salzburg M I 36 contains technical instructions for pump and water-conduit construction inside the same 1425 manuscript that also contains astrology, medicine, prognostics and plant knowledge. Real hydraulic technology therefore belongs inside the same broad medieval technical world as the subjects often associated with Voynich—but visual resemblance to pipes still does not tell us whether Voynich’s tubes are hydraulic.

Quick Read

Salzburg M I 36 was produced at Laubach in 1425.
The Bavarian Academy’s KdiH catalogue identifies folio 70r as containing instructions for pump and water-conduit construction.
The same codex also contains astronomy, astrology, medicine, recipes, plant material and prognostics.
This proves that practical hydraulic technology can coexist with medical-astrological knowledge inside a single fifteenth-century technical compilation.
Mariano Taccola’s early-fifteenth-century Italian engineering manuscripts independently document pumps, water systems, sluices and other machines.
Hydraulic imagery therefore has both Central-European and Italian comparators near the Voynich period.
The presence of tube-like forms in Voynich cannot localise Padua and cannot by itself establish bathing or plumbing.
A genuine hydraulic interpretation must predict flow, source, destination, junction behaviour, pressure/gravity logic and repeated component roles.
If the diagrams fail those tests, the tubes may instead be anatomical, symbolic, classificatory, cosmological or purely connective.

The Eye Wants to Turn a Tube Into a Pipe

Human perception is very good at recognising familiar objects.

That is normally useful.

In an undeciphered manuscript it can become a trap.

A long cylindrical form with openings looks like a pipe.

Once called a pipe, every connected shape becomes plumbing.

Once called plumbing, nearby figures become bathers.

Once called bathers, Abano becomes tempting.

The entire Padua story can grow from one visual classification.

That is why we need a hydraulic null model.

Laubach 1425 Gives Us Real Hydraulic Instructions

The KdiH catalogue for Salzburg M I 36 identifies folios 68v–70v as containing technological, chemical-alchemical and technical recipes and instructions.

At folio 70r, the catalogue specifically notes instructions for pump and water-conduit construction.

This is a major control because the manuscript is dated 1425.

The technology belongs inside the Voynich parchment window.

It is not an early-modern engineering tradition imported backward into the comparison.

The Same Codex Also Contains Medicine and Astrology

The context is even more important than the pump instruction itself.

M I 36 is an astronomical–astrological–medical miscellany.

So technical hydraulic material sits beside:

planetary classification;
prognostics;
medicine;
plant knowledge;
recipes;
body diagrams.

This destroys one weak Voynich argument immediately.

tubes + medicine + astrology can coexist in a German technical manuscript. The bundle is not Paduan by itself.

A Real Pipe System Has Direction

Hydraulics is not simply a visual vocabulary of tubes.

A working water system has operational constraints.

Water has a source.
It has a destination.
Gravity or pressure matters.
Junctions must have a function.
Reservoirs store or regulate.
Valves or controls alter flow.
Pumps create pressure or lift.

These constraints produce testable geometry.

If a Voynich channel repeatedly violates any plausible flow logic, calling it a water pipe becomes less credible.

The Flow-Direction Problem

Many Voynich channels lack obvious arrows.

That does not eliminate hydraulic interpretation; medieval diagrams need not use modern flow notation.

But a hydraulic model should still infer direction from:

elevation;
reservoir placement;
narrowing and widening;
pump components;
entry and exit points;
repeated junction patterns.

If no consistent direction can be recovered, the model weakens.

The Figure–Conduit Relation Is the Hard Test

Voynich often places human figures inside or adjacent to the tubular system.

A literal bath interpretation says the figures are people using the water infrastructure.

That predicts practical relationships.

Figures should occupy plausible bathing positions.
Channels should deliver or remove water.
Pools should connect in physically meaningful ways.
Repeated vessel shapes should have stable hydraulic roles.

If figures instead occupy impossible pipe junctions or behave as labels, personifications or category markers, a literal hydraulic reading becomes less likely.

Hydraulic Diagrams Can Be Schematic

A medieval engineering diagram need not be a modern blueprint.

It can distort scale.

It can combine several views.

It can represent function symbolically.

This means a lack of realistic perspective does not automatically defeat a technical interpretation.

The key question remains:

does the diagram preserve the relationships necessary for a trained reader to understand the system?

Taccola Gives Us an Italian Engineering Control

Mariano di Jacopo, known as Taccola, worked in Siena during the first half of the fifteenth century.

His De ingeneis and related technical manuscripts record a broad range of contemporary machine practice.

Modern histories of technology associate his manuscripts with pumps, water mains, sluice gates, mills, bridge systems and other engineering devices.

Taccola is not Paduan.

That is exactly why he matters.

Technical hydraulic imagery was available in fifteenth-century Italy outside Padua.

This strips geographic value from “Italian-looking engineering” unless the operation is locally distinctive.

Kyeser Gives Us a German Engineering Control

Konrad Kyeser’s Bellifortis provides another technical-image tradition from the German-speaking world around the opening of the fifteenth century.

The Bayerische Staatsbibliothek describes the work as an illustrated technical manuscript of machines and devices, with early versions associated with the first years of the 1400s.

Again, the exact machine types differ from Voynich.

The control demonstrates the wider culture of diagrammatic engineering.

Padua does not own the category.

A Tube Can Represent More Than Water

Before committing to hydraulics, alternative functions should remain live.

Anatomical conduit: vessel, duct or internal pathway.
Process conduit: transfer between stages in a technical or pharmaceutical operation.
Cosmological connector: relation between regions or spheres.
Taxonomic connector: visual line showing membership or descent.
Symbolic boundary: separating rather than carrying.
Decorative scaffold: organising figures spatially.

A good interpretation must beat these alternatives.

The Anatomy Problem

The Voynich tubes sometimes look organic.

That encourages anatomical readings.

If they represent internal vessels or ducts, we would expect:

consistent attachment to bodies;
branching patterns;
repeated correspondence with body regions;
less dependence on gravity;
perhaps symbolic rather than physical scale.

These expectations differ from hydraulic ones.

The manuscript itself can therefore adjudicate between models.

The Process-Diagram Problem

A conduit can also represent transfer in an abstract process.

Modern flow diagrams use arrows.

Older technical diagrams can use spatial connection without explicit arrows.

If Voynich’s tubes connect states rather than liquids, their geometry may encode order rather than plumbing.

This would explain why some forms appear physically implausible yet structurally repetitive.

The Abano Problem Revisited

The Euganean baths remain a legitimate historical comparator.

But after Laubach, Taccola and other engineering controls, the chain:

tubes → water → baths → Abano → Padua

is far too weak.

Every arrow requires evidence.

The tubes must first behave like hydraulic conduits.

The hydraulic system must then behave like therapeutic bathing infrastructure.

Only then does regional comparison become meaningful.

A Hydraulic Test Matrix

Source: identify where fluid enters.
Destination: identify where it leaves or is stored.
Direction: infer a consistent flow.
Energy: identify gravity, pump or pressure logic.
Components: classify repeated junctions, reservoirs and outlets.
Human interaction: test whether figures use the system plausibly.
Cross-page grammar: see whether repeated components preserve repeated functions.
Text correlation: test whether the same textual labels recur with the same component types.

If the system cannot pass these tests, literal hydraulics should lose weight.

What the Hydraulic Controls Can Legitimately Support

Pump and water-conduit knowledge existed in a German technical-medical miscellany in 1425.
Engineering diagram culture existed in fifteenth-century Italy and the German-speaking world.
Technical hydraulics could coexist with medicine and astrology.
Tube-like imagery therefore has multiple historically plausible technical contexts.

What They Cannot Support

that Voynich’s tubes carry water;
that its figures are bathers;
that its channels depict Abano;
that the manuscript is an engineering manual;
that technical diagrams localise Italy or Germany by themselves.

Research Sources

Continue the Series

The Final Idea

The tubes remain interesting.

They are no longer allowed to become pipes simply because the eye recognises them that way.

A real hydraulic interpretation must behave like hydraulics. Until the Voynich channels reveal flow, components and repeatable physical logic, “pipe” is a hypothesis—not an observation.

Voynich and Padua | The Water-Conduit Problem: Pipes, Pumps and the Danger of Reading the Tubes Literally