Of Dyke Squares and Dog Holes

Reading books on subjects that you're not interested in is, in itself, pretty interesting. Recently I read two books about Draughts (or Checkers), "The Wonderful World of Checkers and Draughts" and "The Science of Checkers and Draughts" and I was surprised at the colourful jargon that has grown up around what is – at first glance – a simple game.

While I read, I came across evocative terms such as Dyke Squares ( a square which forms a line of your pieces when you move into it) and Dog Holes (a square which you cannot move out of once you've moved there).

At times, it felt more like I was reading about Poker, with the player Jules Leopold being described as "... strictly a "crossboard" player and, like the late "Sunset" Bell, enjoys playing for strokes and traps."

Add to these phrases like the "delayed steal", the "American position", "Payne's draw", having "the move", being "game up" or "man down", the "in-and-out shot" and the "big theft." I think that Draughts could be one of the more peotic board games I've come across.


References

T. Wiswell, J. Leopold, "The Wonderful World of Checkers and Draughts", 1980, A.S.Barnes and Co., Inc

T. Wiswell, "The Science of Checkers and Draughts", 1973, A.S.Barnes and Co., Inc

Life Drawing 11/03/12

Last Sunday I went to a longer than usual life drawing session with a single four hour pose. My plan was to keep redrawing the same thing to try and force myself to keep looking at it anew each time. Was a bit of a struggle, but I have to admit that the last two were my favourites.

Everyone gets a share of the pi

While reading about the history of mathematics in Japan I found a mathematical sequence which, for reasons I do not know, happens to contain a lot of the estimates for pi that have been put forward throughout history.

This sequence was discovered by Seki Kōwa and was published in 1712 after his death in a book called Katsuyō Sanpō. It runs as follows:

Start with the fraction 3/1. If this number is lower than pi, then increase the upper number by 4. If it is greater, then increase it by three. Then increase the lower number by one. And continue like this.

If you do this, you get a sequence of numbers that includes the estimates of pi from different people from different times in history. In this list (mostly Chinese mathematicians, since up until then Japanese maths was heavily influenced by Chinese textbooks), Kōwa finds the values from Chih (25/8 or 3.125), T'ung Ling (63/20, or 3.15), the “old Japanese” value (79/25 or 3.16), Liu Chi (142/45 or 3.155), Hui (157/50 or 3.14) and also 355/113 (which is very close to the actual value of pi at 3.14159292) but this isn't credited to anyone, so Kōwa must've known about it's use as a value of pi, but not known that Tsu Ch'ung-chih had found it.

I like mathematical sequences that seem to have a narrative, although I doubt it has any use. I don't think the series converges on the true value of pi (I haven't checked) but it does occur to me that this isn't a very good way of calculating pi, because it only works if you already know the value of pi.

Reference
D.E. Smith, Y. Makami, “A History of Japanese Mathematics”, Open Court Publishing Company, Chicago, 1914, p111-112

S.S. Ithaca

On the 3rd May 1875 a steamship, the Kynance was rammed in "thick weather" at four in the morning off St Ive's Head by an unidentified steamship. All twelve of the crew escaped on a boat, but the ship that rammed them continued on its course and didn't heed their calls for help.

Later the S.S. Ithaca was identified as the ship in question and it was impounded at Bristol.

Pity about the white blob covering the text.
And although this story calls the sunken steamer "Hynance",
every other source calls it "Kynance"

But oddly enough, another ship was rammed and sank on the 3rd May in that area by an unidentified steamship. The Talbot (a schooner) was hit off Trevose Head and it's crew were later picked up by The Flying Cloud and taken to Padston.

I did a bit of searching and found that the S.S. Ithaca was in Falmouth on the 2nd May, so to get to Bristol it would have gone past those two locations, in that order. It seems quite a coincidence that there were two different unidentified steamers running into ships that day (though not impossible: I've read that in the mid 1800s you could see three hundred ships from the island of Lundy). The closeness of location and time certainly makes me suspect it was the same ship.

Maybe it was captained by a particularly ruthless sailor who considered it everybody else's job to get out of his way, or maybe it was an ineffectual, slightly comical captain who was just having one of those days.


References

The Daily News (London), Monday 10th May 1875

Royal Cornwall Gazette, Saturday 15th May 1875

Richard Larn, Bridget Larn, "Shipwreck Index of the British Isles, volume 1, The West Country", Lloyd's Register of Shipping. 1995

Life drawing 27/02/12