Stanley vulcanite railway curves
I recently came by a set of W.F. Stanley railway curves made of vulcanite (also known as ebonite or hard rubber), included almost as an afterthought to an ebay listing…
Sketchy calculation
As a bit of weekend fun, here's something called a Rechenstift - German for "calculating pen" - by the venerable Hamburg firm of Dennert & Pape, erstwhile inventors of the…
Fan scales
A recent discussion with Peter Hopp of Slide Rules fame, prompted by an item in the latest UKSRC Newsletter, finally encouraged me to photograph some of my fan scales. This type of…
OK Computer
It is a well-worn truism that nothing is certain except death and taxes, and certainly throughout history much effort has gone into making sure that the latter is as inescapable…
Class of the Titans
A recent discussion about instruments named after mythological figures brought to mind the "Titan" Combination Compass, a simple design that aimed to provide a full drawing set in a box.…
The Fourth of July
Happy Independence Day to all my readers from the USA! In honour of the day, I have posted a photo I took a few years back during a visit to…
Plumbago, Canada!
Happy Canada Day to all my Canadian friends! This year to mark the occasion I decided to dig deep - beyond the ubiquitous Schoenner and Eichmüller wallets, past my lovely…
The Armstrong scale: a hypothesis
Among the more ubiquitous instruments named after their inventors - from Captain Field's parallel to the Napier compass, Gunter's chain to Marquois' triangles - arguably the most widely known and…
Rules are made to be broken
When is a rule not a rule? When it's four rules! This deceptively simple rolling ruler offers an unexpected "twist" on the conventional design. Made of what appears to be…
More patent sticks
Here is a trio of glorified wooden sticks for ruling parallel lines that each somehow managed to secure patent protection. Two are so similar that they could easily be mistaken…