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
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
The Gerber Variable Scale, described here, is a thing of beauty and elegance, admirable for its ingenuity and craftsmanship. It is also a “one of a kind” device, or so I thought until my unexpected sighting on eBay of the “Proportional Rule” made by the Data Scaler corporation of Westfield, Massachusetts. This device is a … Read more
