The Linked Open Data solution for pre-1971 British currency

One of the things I’m working on this summer is the graph structure for Visible Prices — the way that the information will be organized. “Graph” is the technical term used by semantic web programmers for groups of triples that fit together to describe an object.

Just for giggles and gratitude, here are a couple of photographs from DHOXSS 2013, where my classmates and I started figuring out what the graph structure for VP might look like.

I’ll have more on the current structure soon, but this afternoon, I’ve actually been working on a related aspect of the project — namely, the dataset for pre-1971 British currency values. Today, the UK has a decimal currency similar to that of the US and other countries, where there are 100 pennies to the pound/dollar/euro etc. Before 1971, however, (and more importantly, in the 18th and 19th centuries), the values looked like this:

farthing: 1/4 penny

halfpenny: 2 farthings

penny: 2 halfpennies/4 farthings

sixpence: 6 pennies

shilling: 12 pence

pound: 20 shillings

guinea: 21 shillings

Every entry that goes into Visible Prices has to have a price, and they all have to be connected together, so that I can pull back everything that costs 5 shillings, or 5 shillings 6 pence, or whatever.

Early on in the project, I thought I would be dealing with the different values by having the computer do a bunch of math. Then, when I thought I would build VP using MySQL, I figured I’d have a table of values, running from 1 farthing up to a not-quite infinite upper limit. I thought I’d probably write a little program in Java or Python to make me a list of all the different prices, in order to save myself the trouble of writing them all out — still, while the idea of having that table of values sounded great, I was always a little bit sad that it would just be a mass of values stuck on my server.

That sadness was one of the reasons that I got really excited when I learned about linked open data — because the whole idea was that I could create a dataset for all those values, and make it something that other people and projects could use. After all — my project isn’t the only one working with economic information. (See Trading Consequences; and Kathryn Tomasek’s article in JDH on encoding financial records). At the University of Washington, the Newbook Digital Text project encoding Emma B. Andrews’ diaries is also dealing with a bunch of different monetary amounts.

A shared dataset of amounts would help make projects that include economic information conversant with each other — and that would be brilliant.

However — in linked open data, it’s especially important not to reinvent the wheel. If a dataset already exists, then a duplicate version will only create redundancy and confusion. As a result, I spent most of this afternoon scouring the web to find out whether or not such a dataset already existed. While Wikipedia (which is built with linked open data) includes pages on pre-decimal British coins, like this entry for the penny, and while that page includes the note that a penny is 1/240 of a pound sterling, that doesn’t fulfill my needs. It doesn’t have pages for four pence, or eight pence halfpenny. And the idea behind the semantic web isn’t that computers do math — it’s that users can point at a stable definition. (If this is new to you, then 5StarData has some great examples).

The only way to find out whether something like this exists is to go looking — so I did: checking this registry, and Swoogle, which though no longer active, is still a pretty useful place to go looking. I also did a number of keyword searches, which led me to ontologies for numismatics — but focusing on the features of coins, rather than their identifier of value.

Looking for vocabularies and datasets is entertaining: I found a vocab for whiskey, and another one for ancient wisdoms. There are even datasets specifically for food.

There is not, however, a dataset of currency amounts starting with a farthing, and working up. I wasn’t really surprised — I spent some time searching last summer as well, and didn’t find anything — but then I had to let VP go into hibernation so that I could focus on finishing the diss. I’ll do a bit more looking, and ask around, but it looks like I need to see about automating that list of amounts, and read up on best practices for creating URIs. I’ll say a little bit more about that in a few days.