You know I love ephemera, (see here for lots of posts on the subject). It’s amazing, the bits of paper you find, when rooting around for things. Today I found this:
I bet you thought slide-rules were just used for maths! Actually most of you will never have come across a maths slide-rule. By the time I took Maths O-Level in 1976, the first calculators were replacing log tables, and the era of the slide-rule was over; I had one but barely learned how to use it.
This one, isn’t for calculations though, but for musical scales and key signatures. It was published by the OUP in the UK and printed in Japan.
But what’s inside? I hear you cry… a musical slide-rule of course.
There’s a pair of double-sided cards with musical staves which slide in and out of the sleeve. One card has the treble clef, and one the bass. You set the key – major or the relative minor in the little windows at the top, and you’ll see by pulling the insert out, it exposes the key signature for the selected scales. G Major has 1# sharp. Pull out a bit further….
Here we have C# Major (A# Minor) with all the sharps.
The notes then show you where the scale starts – do-ray-mi and so on. The info on the right explains about the two types of minor scales, and you can read off which notes form chord triads.
Then swap the cards around, and/or turn over and you can get the bass clef and/or the key signatures with flats. Here I’ve chosen the flats…
It was such fun, playing with this musical slide-rule. My late mum bought it in the late 1960s or early 1970s I think – it’s not dated, but I remember it living in our piano stool and playing with it, rather than using it when I was studying music theory! Despite the torn cover, I’ll be putting this safely back – into my piano stool this time!