Proposed Manuscript Chronology

[Jorge_Stolfi]

Your point on the S plot however, is not accurate. A Guttman Horseshoe can manifest a more complex shape than an S. Voynich manifests the W shape, as shown below, and in my OP.

The point of my third figure is not the shape of the smudge, but its continuity and smoothness.  

In order to claim that the points are best modeled as a "smoke trail" -- a compact prob distribution D(t) that depends on a gradually varying parameter t -- rather than a "cloud" or multiple "clouds", the density of points must change gradually along the curve C(t) of the centroid of that distribution.  Like in my figure #3.  Preferably in a bell-shaped fashion, with the density increasing and decreasing smoothly along the curve, with a single density peak around the middle of the curve. 

But that is not the case for the VMS page points.  The distribution is much more like my figure #2, with 4-5 dense clumps -- coinciding with the major sections -- that are separated by areas of much reduced density.   The clouds are even elongated in different directions, that are not parallel to the alleged direction of the "gradient".

The few missing folios cannot explain those gaps between the clouds.

The distributions overlap somewhat (at least in that 2D projection) which may give the impression of a singe cloud -- if you do not actually count dots per area.  But that is not enough to justify a "smoke trail" model instead of a "five clouds" model. 

Moreover, we do not expect any text statistics to show a smooth consistent change from page to page, whether the pages are considered in chronological writing order, in intended reading order, or in the order which they were eventually bound.  Between sections, the statistical differences are expected to be dominated by the  change of topic and the changes of style that go with that.  Within most sections, we expect random variations around a single mean.  

In the Herbal sections, for example, the text on each page surely is about the plant depicted there.  Quite probably the plants are in random order, like in the "You are not allowed to view links. Register or Login to view." In that case, the word frequencies of two consecutive pages should be just as similar as those of two distant pages -- and all statistics I have seen used for page comparison and sorting are determined by the word frequencies.

A similar argument applies to the Astro/Cosmo, Zodiac, Pharma, and Starred Parags sectons.

The Bio/Bathing section is the only one where we could expect some statistical continuity if the pages are considered in the intended reading order. The reasoning is that, if the text starts digressing on one page about how scalp massage benefits an ingrown toenail, it is somewhat likely that "scalp", "massage", and "toenail" will be mentioned also on the next page.  However, this effect is likley to be small compared to the sampling noise and to the noise due to sub-topics that are exhausted within a single page.   Thus, if one tries ordering the pages of Bio by any statistical similarity criterion, the resut may look like a continuous gradient, but the order and the gradient will be nonsensical -- like what one gets by ordering books by size.

All the best, --stolfi