Scroll Length?

[William Schryver]

Wrong. The tracings were digitized and converted into single-valued functions. The digitized functions were checked against the tracings for accuracy. No human measurements were involved.

You did tracings of three separate fragments, glued to three different sheets of backing paper of varying sizes. In order to return any kind of value for the edges, you would have to establish a baseline, a zero point, across each fragment. How did you go about establishing this baseline? How did you assure that the baseline was the same for each fragment?

[Fifth Columnist]

Will, I think the onus is on you to demonstrate that deterioration and other effects haven't adversely affected your thickness measurements:

http://cool.conserva...12/bp12-10.html

Some of the papyri exist only as very small piles of fragments, others are intact as rolls (some well over 20 feet in length) but are inaccessible to scholars and the public because their deteriorated condition prohibits their unrolling, study or exhibition. The majority of the papyri, however, upon entering the collection in the 1930's and 1940's, were flattened and cut into shorter sections from the original rolls, and sandwiched, often randomly, between glass and sealed with tape. These glass sandwiches were stacked in large, heavy drawers located in an uncontrolled climate area of the Museum until 1990, when they were moved to the Museum's newly renovated, climate controlled storage.

The general condition of the papyrus collection in The Brooklyn Museum is poor as a result of age, improper previous treatment, questionable housing methods, and poor climate control. Most of the condition problems found on the papyri were similar to those often seen with works on paper. For example, previous restorations such as Western paper backings and repairs made with many small pieces of pressure-sensitive tapes were noted. Inherent problems included deterioration of the papyrus from the corrosive action of copper-containing pigments and flaking paint. Staining and resinous-like accretions were found on the surfaces of many pieces. Environmental factors influence the condition of papyrus as well. Fluctuations in humidity contributed to the growth of mold and to salt migration on the surface of many papyri stored within glass sandwiches. Evidence of insect damage was observed with associated losses in the papyrus. Several pieces have symmetrical losses which span the sheet, indicating the damage occurred while the papyrus remained rolled. In a few cases, inactive egg casings were found as well as insect impressions in the paint layer.

Here is a description of papyrus deterioration in general.

http://books.google....oration&f=false

This is a nice illustration of papyrus deterioration.

http://www.lib.umich...ystem#sec-rolls

The JS Papyri have obviously deteriorated. I think you are making a huge assumption that the deterioration has no effect on the thickness.

Edited November 14, 2011 by Fifth Columnist

[William Schryver]

Will, I think the onus is on you to demonstrate that deterioration and other effects haven't adversely affected your thickness measurements:

I've actually quantified the extent to which the deterioration has affected the thickness measurements! I posted an extract from my article detailing what effect could be observed from deterioration.

It causes the thickness to be increased on account of the fact that the layers of papyrus begin to separate!

The JS Papyri have obviously deteriorated. I think you are making a huge assumption that the deterioration has no effect on the thickness.

I have made no "huge assumption". Quite to the contrary, I documented the observed damage, as well as its effect on the measurements we were making. An analysis of that effect is what leads us to conclude both that the scroll of Hor was tightly wound from an inner core, and that the inner windings would have been likely to measure even thinner than did JSP-X, which averaged ~150 microns.

[rodheadlee]

Rolling up nautical charts leads to insanity, I suspect it's the same with papyrus.

[Fifth Columnist]

I've actually quantified the extent to which the deterioration has affected the thickness measurements! I posted an extract from my article detailing what effect could be observed from deterioration.

It causes the thickness to be increased on account of the fact that the layers of papyrus begin to separate!

So you're saying that the only effect thousands of years of deterioration coupled with improper handling (sandwiched between pieces of glass, etc.) had on the papyrus is to cause the layers to separate and increase its thickness? If so, then wow.

From your explanation, you didn't do anything to account for the deterioration other than measure various areas of the papyri. This would not identify effects that impact all the areas equally (e.g., being smashed underneath a piece of glass while it is transported to the museum in Chicago in a wagon). There is a reason thickness is not a variable in the formula Egyptologists use to calculate the length of a papyrus roll.

I have made no "huge assumption". Quite to the contrary, I documented the observed damage, as well as its effect on the measurements we were making. An analysis of that effect is what leads us to conclude both that the scroll of Hor was tightly wound from an inner core, and that the inner windings would have been likely to measure even thinner than did JSP-X, which averaged ~150 microns.

Yes, this is precisely the problem. Your measurements have no way of identifying and controlling for deterioration that affects all the papyrus equally. You need a lot more data to demonstrate that the current thickness is the same as the thickness when it was originally rolled up.

[Mortal Man]

No, I do not believe that if you take two rolls of toilet paper with the same circumference--with one having paper that is twice as thick as the other other (the kind I like)--that the length of the toilet paper will be the same in both rolls. This seems absolutely certain to me.

Now try burnishing your toilet paper with a stone and writing on it with with a reed pen, or even a rush pen. The Hor papyrus originally possessed sufficient texture that the ink sometimes failed to fill in grooves on the recto side. The verso would have been even rougher. You wouldn't have been happy with it.

The fact that Smith/Cook have not actually measured the JS papyri,

Wrong

had not applied their methodology on any known papyri,

Wrong

do not take the thickness of the papyri into account,

Wrong, it's automatically accounted for in the winding lengths.

and reject the measurements of known papyri rolls

Wrong

that don't match their theory

It's not our "theory". It's a well-tested time-honored formula that Gee went on and on about in the FAIR WIKI because he thought the critics didn't understand it. The formula does not call for thickess. To force a thickness into it is to deny the winding lengths. This is simply wrong. You can't make applesauce out of oranges.

leads me to reject their claims.

You did that long before you even knew what our claims were.

Given the same circumference, the actual length of the scroll will be dependent on two variables, the thickness of the papyri, and the tightness of the winding.

Wrong, it depends only on the winding lengths, which include all the the essential thickness and tightness information. The thickness of the papyrus changes over the centuries, as a result of aging and dessication, but the windings remain constant.

The fact that Smith/Cook must reject this to make their theory work seems to invalidate their theory.

For the last time, as far as our paper is concerned, we've rejected nothing regarding the thickness measurements. The current thickness of the papyrus is an entirely separate issue.

[wenglund]

Will, have you identified a representative sample of scrolls from the relevant period or are you simply trying to show that was one or two scrolls that were thin at the same time?

http://books.google....epage&q&f=false

Will needs the papyrus to be very thin to support his subjective, photograph based winding measurements. The thickness sets the outer bound for Will's measurement so he needs it to be small. MM and Chris's winding measurements were performed on a tracing of the actual papyrus and the windings were identified using an objective mathematical algorithm. I think the latter is a much better methodology than the one used by Will.

You evidently still don't get it. In Will's case, the thickness of the papyri is determined by actually measuring the thickness of the papyri. The measurements that Will professionally obtained, are shown via the cited example to be consistent with other papyri of the period.

Whereas, in MM's case, the thickness of the papyri is a by-product of his winding measurements, which conflict significantly with actual professional measurements of the papyri.

Here is why MM's formula is potentially problematic: with the formula that I and perhaps Will has been using, any inaccuracies in measuring the winding lengths will have but a one-to-one impact directly on a single variable--i.e. the winding lengths in general, and the circumference of the outermost winding in particular. Whereas, with MM's formula, inaccuracies in measuring the winding lengths will have an exponential impact not only on the length of the scroll, but also on the thickness of the scroll. And, with the kind of inexact measuring technique at the heart of their calculations (based on a hand-drawn outline), the exponential factor can wreck havoc with the numbers, potentially distorting them to the point that the results appear absurd in the face of reality--as evinced by how radically different MM's thickness measurement ended up in comparison with what was professionally measured.

Thanks, -Wade Englund-

[William Schryver]

There is a reason thickness is not a variable in the formula Egyptologists use to calculate the length of a papyrus roll.

You mean because it has something that has never been done before?

(You should really back out of this discussion right now. With each post your ignorance of the subject matter becomes increasingly apparent.)

Egyptologists have never, historically, attempted to calculate the length of a papyrus scroll based on its surviving fragments. To my knowledge, John Gee and I are the only people to ever attempt it.

Papyrus thickness is not a value anyone has ever attempted to determine. The way I conceived of doing it will constitute the first time anyone has developed a methodology for measuring the thickness of papyrus in a preserved status. John Gee is submitting to several Egyptological journals a short article describing the innovative methodology.

Yes, this is precisely the problem. Your measurements have no way of identifying and controlling for deterioration that affects all the papyrus equally. You need a lot more data to demonstrate that the current thickness is the same as the thickness when it was originally rolled up.

Again, you have no idea what you're talking about. All you're doing here is waving pom poms for your team. Rah! Rah!

[Mortal Man]

That is a huge assumption to make, especially when it is based on actual measurements of only the outermost three windings.

For the last time, we measured eight windings.

[Mortal Man]

I have no reason to believe the Cook/Smith formula to calculate the total length is flawed.

Then you have no reason to introduce a flaw by forcing thickness into it.

No, I believe their formula to calculate the winding lengths is where one will find the flaw.

You mean the autocorrelation function? I suppose to your way of thinking we just made that up. Unfortunately, unlike your "substantial word analysis", our "formula to calculate the winding lengths" has a long history.

One need only examine their methodology as they describe it to realize there are several elements subject to error, beginning with the way they obtained their data (manually tracing the edges of the papyrus).

Once again, anyone and everyone is free to compare our tracings against the originals.

Edited November 14, 2011 by Mortal Man

[William Schryver]

It's not our "theory". It's a well-tested time-honored formula that Gee went on and on about in the FAIR WIKI because he thought the critics didn't understand it.

You're being intentionally evasive here. No one is questioning your methodology to calculate the length of the scroll. What's being questioned is your methodology for determining winding lengths. Of course, you know that. You're just hoping you can bluff your way past those readers who aren't able to make that important distinction.

The current thickness of the papyrus is an entirely separate issue.

The thickness of the papyrus is a control on your methodology. It indicates that your methodology is flawed.

[William Schryver]

For the last time, we measured eight windings.

No. Your questionable methodology, using input data produced by a hand-tracing of the papyrus, while mounted inside a mylar sheath, output measurements for eight windings. It remains to be seen if that methodology will withstand scrutiny. But you didn't actually measure any windings.

Furthermore, the known thickness of the papyrus, used as a control, indicates that your methodology is profoundly flawed.

Edited November 14, 2011 by William Schryver

[wenglund]

Wrong. The tracings were digitized and converted into single-valued functions. The digitized functions were checked against the tracings for accuracy. No human measurements were involved.

The tracing wasn't by a human?

Thanks, -Wade Englund-

[Mola Ram Suda Ram]

The thickness of the papyrus is a control on your methodology. It indicates that your methodology is flawed.

And that is the heart of the matter and really the issue, I think, that keeps getting glossed over by the critics. Interesting that.

[Bill Hamblin]

Now try burnishing your toilet paper with a stone and writing on it with with a reed pen, or even a rush pen. The Hor papyrus originally possessed sufficient texture that the ink sometimes failed to fill in grooves on the recto side. The verso would have been even rougher. You wouldn't have been happy with it.

Wrong

Wrong

Wrong, it's automatically accounted for in the winding lengths.

Wrong

It's not our "theory". It's a well-tested time-honored formula that Gee went on and on about in the FAIR WIKI because he thought the critics didn't understand it. The formula does not call for thickess. To force a thickness into it is to deny the winding lengths. This is simply wrong. You can't make applesauce out of oranges.

You did that long before you even knew what our claims were.

Wrong, it depends only on the winding lengths, which include all the the essential thickness and tightness information. The thickness of the papyrus changes over the centuries, as a result of aging and dessication, but the windings remain constant.

For the last time, as far as our paper is concerned, we've rejected nothing regarding the thickness measurements. The current thickness of the papyrus is an entirely separate issue.

There's a lot of obfuscation going on here.

Let me ask one simple question, and see if I can get a simple clear answer.

Imagine a papyri roll of a certain circumference.

a- Is the thickness of the original papyri a variable in how long of a scroll you could wind into that circumference?

b- Is the tightness of the original winding a variable in how long of a scroll could be wound into that circumference?

[Mola Ram Suda Ram]

Imagine a papyri roll of a certain circumference.

a- Is the thickness of the original papyri a variable in how long of a scroll you could wind into that circumference?

Let me see if I can answer this.

Yes, the thickness could be used as a variable.

b- Is the tightness of the original winding a variable in how long of a scroll could be wound into that circumference?

Yes, the tightness could be used as a variable.

[Calm]

Rolling up nautical charts leads to insanity, I suspect it's the same with papyrus.

Getting close it would seem....

[Mortal Man]

In other words, the thickness variable does matter, right?

When he says "thickness" he really means "effective thickness" not the current physical thickness of the papyri. That is what Egyptologists mean when they relate thickness to winding lengths; i.e., they implicitly derive thickness from changes in winding lengths. The physical thickness of these scrolls may very well be (and almost certainly is) much smaller than 800 microns.

[Chris Smith]

You did tracings of three separate fragments, glued to three different sheets of backing paper of varying sizes. In order to return any kind of value for the edges, you would have to establish a baseline, a zero point, across each fragment. How did you go about establishing this baseline? How did you assure that the baseline was the same for each fragment?

Here is my email exchange with Andrew on that topic, from January 2010:

Hey Andrew,

One more question: how did you determine what was "horizontal" with respect to the papyrus edges in choosing your reference line? Since this is a potential source of bias/experimental error, we may want to talk about it in the paper.

Peace,

-Chris

Good question. I scanned down/up from the top/bottom edges of the tif images you sent me, so the reference lines are parallel to those edges.In lining up pJS 1.1 & 1.2, I noticed that a rotation of about 1 degree is necessary to get them to match. I considered rescanning the image with a 1 degree rotation of the tif but then decided against it for two reasons:1) I don’t think we can be certain of the direction of roll of any of the sections to better than 2 degrees.2) The error in winding length arising from misalignment of the reference line with the direction of roll goes like SIN(phi), where phi is the angle between the two lines. SIN(1 deg)=0.017; whereas, the variation in our three good thickness estimates is ~17%; hence, the misalignment errors are an order of magnitude less than other errors.

I guess what I'm wondering is, is error in winding length the only problem? Doesn't a misaligned reference line also result in a distortion of y-values (since the y-values at one end will be higher than at the other)? How will this affect the correlation?

It will have virtually no effect on the correlation. You can multiply either of the functions by an arbitrary constant without changing C. Since the misalignment is a slow function of x, it’s almost like multiplying by a constant. I think we’re talking about errors in the 5th or 6th digit here, whereas we’re only carrying 4 digits of accuracy.

Edited November 14, 2011 by Chris Smith

[Bill Hamblin]

Let me see if I can answer this.

Yes, the thickness could be used as a variable.

Yes, the tightness could be used as a variable.

So why are Chris and Andrew incapable of clearly stating this?

[Mola Ram Suda Ram]

So why are Chris and Andrew incapable of clearly stating this?

I dunno. I was really hoping they would chime in. That is why I answered, as a sign of good will.

[Mola Ram Suda Ram]

When he says "thickness" he really means "effective thickness" not the current physical thickness of the papyri. That is what Egyptologists mean when they relate thickness to winding lengths; i.e., they implicitly derive thickness from changes in winding lengths. The physical thickness of these scrolls may very well be (and almost certainly is) much smaller than 800 microns.

No one cares. Sorry but the word "effective thickness" in this conversation seems to be more of a diversion than a point of clarification.

PS: Don't read to much into my snarkiness.

[Fifth Columnist]

You mean because it has something that has never been done before?

(You should really back out of this discussion right now. With each post your ignorance of the subject matter becomes increasingly apparent.)

It wouldn't be a thread with Will Schryver if this kind of stuff wasn't included in heavy doses.

Papyrus thickness is not a value anyone has ever attempted to determine. The way I conceived of doing it will constitute the first time anyone has developed a methodology for measuring the thickness of papyrus in a preserved status. John Gee is submitting to several Egyptological journals a short article describing the innovative methodology.

Yeah, this is sounding more and more like your "substantial word analysis." How did you account for things like storage in glass stacked on top of each other for many years (see Brooklyn Museum article I linked to above)? Here's a hint, that kind of storage will smash the papyrus. Also, how do you know how much deterioration is due to exposure to increases humidity, etc. (all the types of deterioration described on the other sites I linked to)? Your measurements simply identified areas where the papyrus separated or one layer had come off, etc. I haven't seen anything in your method that accounts for the many other ways papyrus can deteriorate.

[Mortal Man]

More accurately: from hand tracings of the papyri, and then human measurements of those tracings

You have no basis for criticizing our readily available tracings until/unless you compare them to the originals.

There were no "human measurements of those tracings". Once we verified an exact match between our digital and analog data, it was essentially an automatic process.

input as data into a formula of questionable reliability.

I welcome you Will, to criticize the reliability of Pearson's correlation function in your paper.

[Fifth Columnist]

So why are Chris and Andrew incapable of clearly stating this?

Tightness and thickness are certainly variables in how much you can wind anything. However, Egyptologists have determined that winding lengths account for both of those variables as well as all other variables such as deterioration so that only winding lengths are used to estimate the length of a papyrus roll.

If Will wants to rely on thickness to show the length of a roll, then he will need to do the heavy lifting to show that it can be reliably used this way. He is the one who needs to do all the tests you challenged MM and Chris to perform (test it on existing papyrus, account for deterioration from oxidation, age, humidity, etc., etc.). Will is the one who is breaking new ground with his method. MM and Chris used the already established and proven method.

Edited November 14, 2011 by Fifth Columnist