The Abacus

I have just read an extremely interesting book The History of the Abacus by J Pullan. It is very odd the way one thing leads to another. I was reading a history of the Moors in Spain - after being in Spain. There was an odd paragraph at the end of the book about Arabic numerals and Roman numerals and a remark that the Exchequer in London was so called because they used a chequered cloth on a table as an abacus. What?? So I delved in Wikipedia and sure enough, they used to order up a new table cloth for the Exchequer twice a year (!!!) and it was said that the cloth looked like a chess board hence the name. We are talking 13th to 16th century here. Well nothing said in Wikipedia or any where else on the web actually told me how this worked. So I looked up Amazon and ended up with one book - by J Pullan. In Amazon's curious way, it cost 0.89p plus £2.80 postage. I thought I could afford that as a gamble - and it is a wonderful book. I now know how it worked. He deals with the history going back a long way.

The Darius Vase above shows someone manipulating the counters on the table before him with his right hand and writing the answer down in thing looking remarkably like an Ipad in his left hand. This is dated 330 BC. Quite extraordinary.

It is just as well there is something to cheer me up. My session on drafting today ran in choppy waters over explaining huck. I shall have to write a much longer explanation and see if I can do better.