At the Uni of Exeter, a project to build a Bronze Age boat is under way - and they now have a time-lapse video of the first four weeks:



They're planning to publish another video in a few weeks' time - so everybody can sort of keep up with the process.

Since I had some more little troubles with xmgrace yesterday, I used the Phone-a-Friend Lifeline and did just that. And thus got myself a nice little one-on-one, flesh-and-blood Grace tutorial.

Where I learned the following Two Rules for Getting Grace:
Rule one: If plotting or importing data does not work, you probably have a dumb user problem and screwed up your dataset. Which is easy to do - just add a line break at the wrong place, or leave a string in.
Rule two: When working with grace, pretend it's a jump-and-run game or an egoshooter - save early, save often, save lots of different versions. Grace has no undo function, and hitting the wrong button (or even the right button) at the wrong time can permanently screw up things.

I'm not sure whether there's a third rule - insist on grace being totally cool and a very good tool no matter how much trouble it can make - but I will find that out (probably).

For now, though, I know how to get stuff like this:


so I'm perfectly content.

It really, really is amazing what one can learn (and has to learn) just because of some spinning. I have learned on Thursday last week that Excel will find the median of a list of numbers by... choosing the value in the middle of the list. Which means that instead of finding the statistical median (half of the values are larger than this number and half of the values are smaller than it), it finds the number in the middle of a list. Thank you, Excel, I could have done that myself. By placing a simple link to the cell in the middle of the list. Because yes, I can count! So I worked on a little more, using the average instead, and grinding my teeth (figuratively speaking only, though).


In case you do not have your own version of a spinning experiment that you need to evaluate and analyse, and have no clue what I'm talking about: the average is made by summing up all numbers in a dataset and then dividing it by the amount of numbers. The median is the value in the middle of the dataset. Why do I want the median instead of the average? Median is way less vulnerable to outliers in the data. Case in point - let's assume we have a list of values that goes 1, 2, 3, 4, 100. Average is (1+2+3+4+100) divided by 5, which is 22. In contrast to this, the median of the same dataset is 3.

And Friday morning, I had a little private time with Mr. Google again, and I found out that yes, you can force Excel to get the statistical median. You can tell it to find the x-largest number in a bunch of cells. Which means that if you know how big your list of data is (I do) and see if it's an odd or even number of data (I do) and, if it's even, can divide said number giving the length by 2 (I do) and can make Excel calculate an average (I do) you can tell it to calculate the average between the two numbers in the middle of the list. Gotcha.

Oh, and I need the median... because after some fiddling and trying out and looking at data and getting brain-dead and trying something else, the most patient husband of them all and me came up with a possibility to give relative variations of thread thickness. Which uses a simple formula built around either the median (good) or the average (not quite as good). And now please excuse me while I try to get my now nicely-sized histogram bins into a good graph form.

Which will include giving my computer a split personality - because the programme I plot to do my plotting with is only running on Linux machines.

It really is amazing how much time a single small macro can gobble up.

Especially if, when you are almost through, you decide that the process might be even better suited to the aims if done a little differently. Because it does make a difference whether you run a median filter first, or whether you filter out outliers first, or make a transformation to binary first and run filters later on.

Anyways, I now have a method to turn a scan of thread samples like this:

into this:


and then read out the thread thickness of every single one of these threads.

Now I only need to wrangle the gazillions of datapoints into something resembling histograms or some other form of legible visualisation. And be amazed again at how much time a single little spinning experiment can eat.

Experimental Archaeology is cool. About as cool as the Internet, I would say - there are so many questions about our history still unanswered, and quite a few of them are suitable for designing an archaeological experiment around them.

Plus it's absolutely exhilarating to try out things and find out things at the same time - even if the trying out and finding out involves lengthy mind-numbing and tedious work. (It's a scientific method, after all - you don't get only the fun of doing, you get the work of analysing too.)

And then, impressive things can happen. Plus a successful archaeological experiment is almost always of interest for the public - so it also helps getting people understand how varied and interesting and yet unknown the past is. Case in point? This article here, exploring old alcoholic beverages reconstructed from organic residue in vessels.

Here's to archaeology - cheers!

A while ago, I wrote a teaser post about a plying technique that I wanted to write about - and then I almost forgot I promised you a follow-up post.

While most of the ladies on medieval images have a long distaff that clearly holds fibres, like this:

Psalter of Fecamp. Ca. 1180. From Petzold, Andreas. Romanische Kunst, art in context. Köln: Dumont, 1995, p. 97.

and some fewer ones have a short distaff that also clearly holds fibres, like this:

Detail from Giotto: Annunciation to St. Anna. Scrovegni-Chapel, Padua. 1300-1320. From Flores d'Arcais, Francesca. Giotto. New York: Abbeville, 1995, p. 150.

something about this picture has always sort of tickled the back of my brain.

Young woman, Pseudo-Apuleius, 13th century. Vienna, Österreichische Nationalbibliothek, Cod. Vind. 93. From Kotzur, Hans-Jürgen. Hildegard von Bingen 1098-1179. Mainz: Verlag Philipp von Zabern, 1998, p. 336.

It's not the usual what she's holding; it's clearly a shorter distaff than usual, and the form of the stuff on the distaff is very clearly defined, very spindle-shaped and not fibery-looking at all.

Let's jump to another topic: the problem of plying. I don't know how well you manage to spin the same amount of length on two spindles or spools - I don't manage so very well; there's always some of the yarn left on one side when the other side has already run out. There's a theoretically very easy way to avoid this, though: To fold the yarn spun in half (from one single spindle, spool, or cop) and ply it with itself. When there isn't a foulup, you end up with a neat two-ply with no singles left.

There are different instructions on the 'Net on how to ply from a center-pull ball, and there's also the Andean Plying Bracelet which both are means to achieve the desired end-result: a skein of single folded in half and plied up. Both involve re-winding the spun yarn from the bobbin of a spinning wheel (where it's an absolute necessity) or from a spindle.

Me, I'm lazy. I like to be lazy. I promote winding spindles in a special way so that I can, after spinning, just slide that cop of yarn off the spindle onto a slim bit or stick of wood or so for storage. (Chopsticks, by the way, work fine.) And the way that I wind my yarn results in a stable, spindle-shaped cop of yarn that is essentially something not too unlike a center-pull ball. So I tested plying directly from the  cop (transferred to a slim stick) onto the spindle... and it works, and very very well too.

There's me doing it...

... and a close-up with a slightly different hand position that occurs quite frequently during the process.


So... here's a method that is efficient, easy to use, will result in no waste of yarn singles, and does not require extra tools (you can use a spindle stick to ply from). And I'm hooked on this new technique.

There's this half-joking rule for IT guys and programmers that goes:

If you have a job to do and need to find out how long it will take, do the following.
Estimate the length of time you will need to do the job. Now take that number and increase it to the next number of magnitude - minutes into hours, hours into days, days into weeks and so on.
Now you add three. That's how long it will take.

Maybe I should start to use this rule as a hard-and-steady rule for my work stuff - like getting the webpage overhauled (well, yes, that did go on hiatus for quite a while), the online shop running (I didn't realise how much Holy Saint Bureaucracius would need to be revered) or the Spinning Experiment all wrapped up.

Ah, the Spinning Experiment. Yes, the results have been found and the paper is in the processing; but I have one thing left to do with the data, and that is cleaning it up a little, translating some of the extra info into English and then packing it up nicely for everyone to download from the Forum webpage. And for that, I need to sort through the yarn cop photos.

I took at least three photos from each sample, and I will just upload one, the best one regarding light and contrast. So I need to pick out those that should be uploaded, resize them a bit and then pack them into a .zip file. And that's still left to do. Sometimes I'm really, really amazed at how much time that Experiment gobbled up... though I'd do it again, it has been totally worth it.

And sometime soon, you will get a note on this blog that the data is up...