Jacob Zedak’s wooden slide rule

What’s so special about a wooden slide rule, you ask? And indeed, for most of their 3½ centuries of existence — until the arrival of plastics — the material of choice for making slide rules has been wood… but that is the case with straight slide rules. Circular slide rules, by contrast, were almost exclusively … Read more

The spirit of a fractal!

Jerusalem central bus station

Here is a photo of the Jerusalem central bus station, a large blocky building at the entrance to the city. So, maybe it’s just me, but whenever I see it I get reminded of a mathematical construct – the Menger Sponge, a three dimensional fractal. Judge for yourself: OK, OK, the bus station is not … Read more

A homebrew Single Sideband transmitter

Homebrew SSB transmitter

This new article on my Possibly Interesting site is strictly for radio amateurs and other geeks: a photo-essay depicting circuit and construction details of the SSB transmitter I’d built a long time ago. What makes it interesting (other than the nostalgia of vacuum tubes, that is) is the prevalence of improvised, scavenged and military surplus … Read more

Meet a Mathematical Inventor!

Meet a Mathematical Inventor! 21

This is Jaen-Antoine Lafay’s Hélice a Calcul, a rather unusual logarithmic slide rule. But Lafay himself, its inventor, was just as unusual, not to say quirky… a fascinating lone innovator waging war on an indifferent world. To illustrate, here is a section from Lafay’s marketing brochure: Oh, routine! What wrong do you not do, firstly … Read more