‘13. Devonshire oil-stone is an excellent variety for sharpening all kind of thin-edged broad instruments, as plane-irons, chisels, &c., and deserves to be better known. This stone was first brought into notice by Mr. John Taylor, who met with it in the neighbourhood of Tavistock, and sent a small parcel to London for distribution; but for want of a constant and regular supply, it is entirely out’of use here.’
It’s not much to go on is it?
That extract from Richard Knight’s 1836 letter detailing The Principal Stones Used in the Mechanical Arts is about the sum total of the information we have about the so-called ‘Devonshire Oilstone’. And even then Mr. Knight account cannot be assumed to be the most reliable of sources; later on for instance he appears to mix up the Belgian Coticule and German Thuringian hones.
Recently though its existence and identification have occupied the minds of a number of people. Perhaps the most extensive search and research was done about ten years ago by a member on SRP, who unfortunately time and again found that any definite knowledge of the stone has since been lost. Though did discover a single more concrete piece of information, which appears to be a transcription of a presentation given by the same Richard Knight as above:
‘This stone occurs near Huel Friendship Mino, about three miles from Tavistock, in the Devonian slates of that district... it has not, however, become an article of commerce.’
- - -
Here then are the first assumptions I’m going to make... the Devonshire Oilstone is a type of slate occurring around the tiny village of Mary Tavy (where the Jewell Friendship Mine is found). And that it was never quarried specifically as a hone stone.
- - -
My sister lives relatively close to Tavistock and Mary Tavy, and I’ve been there a couple of times recently. Yesterday for instance we went walking around there on a route that took in five or six disused quarries. Though we were a few miles south east of Mary Tavy, due east of Tavistock, at the start of Dartmoor. And by that point the quarries seemed to be for granite, some were unidentifiable, others looked like this:
Though at the very end of our walk I came across something a little more promising. As far as I can see this is basically a small slag heap of local slate that has been used to elevate the old road across Dartmoor:
And in it, pieces of something quite interesting:
[A fun geology lesson, and pictures of buildings to follow in part two...]
It’s not much to go on is it?
That extract from Richard Knight’s 1836 letter detailing The Principal Stones Used in the Mechanical Arts is about the sum total of the information we have about the so-called ‘Devonshire Oilstone’. And even then Mr. Knight account cannot be assumed to be the most reliable of sources; later on for instance he appears to mix up the Belgian Coticule and German Thuringian hones.
Recently though its existence and identification have occupied the minds of a number of people. Perhaps the most extensive search and research was done about ten years ago by a member on SRP, who unfortunately time and again found that any definite knowledge of the stone has since been lost. Though did discover a single more concrete piece of information, which appears to be a transcription of a presentation given by the same Richard Knight as above:
‘This stone occurs near Huel Friendship Mino, about three miles from Tavistock, in the Devonian slates of that district... it has not, however, become an article of commerce.’
- - -
Here then are the first assumptions I’m going to make... the Devonshire Oilstone is a type of slate occurring around the tiny village of Mary Tavy (where the Jewell Friendship Mine is found). And that it was never quarried specifically as a hone stone.
- - -
My sister lives relatively close to Tavistock and Mary Tavy, and I’ve been there a couple of times recently. Yesterday for instance we went walking around there on a route that took in five or six disused quarries. Though we were a few miles south east of Mary Tavy, due east of Tavistock, at the start of Dartmoor. And by that point the quarries seemed to be for granite, some were unidentifiable, others looked like this:
Though at the very end of our walk I came across something a little more promising. As far as I can see this is basically a small slag heap of local slate that has been used to elevate the old road across Dartmoor:
And in it, pieces of something quite interesting:
[A fun geology lesson, and pictures of buildings to follow in part two...]