Today medical thermometers are electronic contraptions that come in various forms and are easy to use and easy to break – as disposable as most everything seems to be of late. When I was a kid medical thermometers were glass tubes with a thin line of mercury running up on a scale inside it, terminating … Read more
Was waiting to board a plane at Ben Gurion Airport. Boarding was by zones, which is a sensible idea but usually involves some confusion as to which zone is up… PA announcements can get drowned in the general hubbub. So this time, they had a young lady announce the zones at the top of her … Read more
The humble clothespin is a ubiquitous item that has been with us for generations; and it is simple enough that you’d think it’s reached the point if utmost reliability. And yet, it seems that it is in fact very unreliable: clothespins break, they fall apart, they need constant replenishing… but I seemed to remember that … Read more
We all buy LED light bulbs these days (remember the days of CFL and tungsten filament bulbs?). And we buy them in little cardboard boxes made from dead trees. You have skinny single-bulb boxes, and you have twice as wide two-packs. So imagine my surprise when I saw the in-between box at the left in … Read more
Eating at a restaurant can be a romantic occasion, but restaurants seem to feel that justifies keeping a low lighting. Which is fine for romance but annoying when you need to peruse the menu. However, this one restaurant in Milano solved the problem! They had low enough lighting, but on each table they had this … Read more
Here is one impressive calculating device: Washington Sabatini’s reinforced concrete calculator. This complicated circular slide rule is one of the largest items in my collection. It comprises ten concentric aluminum rings covered with complicated scales and pointers. The rings are all movable except for the second largest; that one is fixed to the body of … Read more
The Tavernier-Gravet company was France’s premier scientific instrument maker at the end of the 19th century, and it stayed abreast of the latest developments in slide rule design and production when it entered the 20th century. In this this new article on my History-of–Computing site I illustrate some of their problems and solutions as they … Read more
So what do you do if you want to give a computer to every child, and the computers of your day are made of expensive boxwood? Why, you invent a cheap slide rule made of Glass! Leon Lalanne did, in 1851. Read all about it here!
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
A few years ago I sighted on eBay a set of three German circular slide rules of the Controller brand. There was a big one, 20 cm in diameter; a midsized one 11 cm across; and a small one at 7.5 cm. They all looked pretty much the same except for their sizes, and this … Read more
