Stanley’s first planimeter (part 3)
As November draws to a close, it seemed an opportune moment to conclude my investigation of Stanley's planimeter, at least so far as the instrument itself is concerned. One of…
Stanley’s first planimeter (part 2)
My last post ended with a slew of questions that I had intended to address in a second instalment, but as I began to assemble the evidence it quickly became…
Stanley’s first planimeter (part 1)
November 16th 2023 marks the bicentenary of Jakob Amsler-Laffon's birth - at least according to the more trustworthy sources - so it seemed only fitting to save a rather special…
A Stanley puzzle
The subject of this post is yet another ebay purchase, this time made purely on the basis of a name on a box. Described as geometrical models for teaching, the…
Mechanical Pencil Month – Day 20: Mordan’s Bicentennial
The final day of our countdown has arrived which means it is time to go back to where it all began. By that I don't just mean Hawkins and Mordan's…
Mechanical Pencil Month – Day 17: Slide rules, OK?
Another Slide Rule Saturday rolls around (whatever happened to the last one?) and having already used up my only slide rule pencil as well as my only pencil with slide…
Mechanical Pencil Month – Day 12: Twelve leads a-leaping
For the twelfth day of Christmas Mechanical Pencil Month, I present a whistlestop tour of twelve lead refills from my collection of [insert large number here]. They have been arranged…
Mechanical Pencil Month – Day 10: Mordan’s Centennial
We have already reached the halfway point of our countdown to the bicentenary of Hawkins and Mordan's 20 December 1822 patent for the first mechanical pencil. It therefore seemed appropriate…
Mechanical Pencil Month – Day 8: The Interlock Pencil
Today's post asks the question: What makes a mechanical pencil? Day three's Nestler with its complex double-push action definitely qualifies; the simple cedar pencils of day two, clearly not. Going…
Mechanical Pencil Month – Day 4: The Eversharp 4 Square
Day the fourth be with you! On that note, it's hard to think of a more quadratic pencil than the Eversharp 4 Square. This was a mechanical pencil of square…