Kyle Rankin @kyle@librem.one

These are portable, but are bigger and heavier than other pocket calculators of the time and primarily sat in or on a desk using the kickstand, and were used for quick arithmetic. To add a number, insert a stylus at the corresponding digit and drag down to the bottom.

These are known as chain adders. By inserting a stylus and dragging the chain down, you increment the register. You can see the carry mechanism in this video, which uses a spring-loaded tooth that rides along the outside of the gear and engages with the next gear only after 9.

These are Golden Gem portable adding machines made by the Automatic Adding Machine Company. The chrome one on the left was made around 1910 and the black one on the right, which has its original box, case, warranty card and receipt, was purchased in February 1941 for $9.16.

"If it's free, you are the product" stopped being true once the rest of the companies saw how much money there was in selling customer data. Now you are the product regardless of whether you pay.

It's so profitable to sell customer data that Vizio now makes 2x as much from that than selling TVs. Until the govt outlaws this data collection, your only recourse to protect your ⁨#privacy⁩ is to buy things from the few companies left that respect it. https://gizmodo.com/welp-vizio-now-makes-twice-as-much-from-advertising-as-1848034943

New hobby: I'm taking up weaving! The pun possibilities are looming in my warped mind.

Apple's talking about sideloading this week to shift the discussion away from App Store competition. If it had to compete with other secure iPhone app stores (like ones dedicated to gaming) it would have to lower its fees and improve its policies. It's about control not security.

Division aside though, this is my favorite lever style adding machine in my collection to use, due to the subtraction key and overall key placement that enables one-handed operation. I could actually see myself using this to balance a checkbook if I still did that sort of thing.

Division is repeated subtraction while counting your lever pulls and watching the register for underflows, which is a pain to do, and to demo on this type of adding machine.

Multiplication is repeated addition, shifting left for each digit in the multiplier, like other lever adding machines. By pressing down the repeat key the keys stay depressed after you pull the lever so you press the Correction key to release them and shift left. Here is 12 x 12.

You can hold down the subtotal button and pull the lever to print the current total without clearing the register, or you can hold down total to clear the register and print the total. This design is nice in that you can do it all one-handed.

This machine does have one fancy feature: a subtraction button! Instead of the complements method, you can just enter the subtrahend, hit the subtract key and pull the lever. Subtraction prints in red ink! Here I perform 31342 - 42 slowly so you can watch the counter.

Back to the Model 75. To add, enter the first number in the keyboard and pull the lever to add it to the register and print on the paper tape. Then enter the second number and pull the lever again.

It wasn't until the 1950s that trends changed and popular office machines started having green and grey hues, like this early 1950s NCR 11-EN. One big exception was the Comptometer, which kept its brown tones until the 50s when it too shifted to the green/grey aesthetic.

The Burroughs Class 3 I showed earlier in the thread is an example of rebranding a machine originally made by the Pike company. But when 90% of a market looks a certain way, competitors (like this Monroe Model G from 1918) mimic the design. So even in 1946 RC Allen followed suit.

At one point Burroughs controlled about 90% of the adding machine market. It accomplished this like companies today: it bought up its competitors and rebranded their products. That meant painting them black, and instead of felt, they just painted the spot under the keys green.

The Burroughs Class 1 was the first adding machine Burroughs sold starting at the end of the 19th century. It was the Cadillac of adding machines and featured a shiny black case, beveled glass on the sides to show off the mechanism, and actual green felt under the keyboard.

This machine looks and functions largely the same as Burroughs adding machines 30-40 years older. Have you noticed how many machines I've featured (like this Burroughs Class 3) have a black case, and a keyboard with white and black keys on a green background? My theory for why:

This is an RC Allen Model 75 adding/listing machine from around 1946. RC Allen was founded in 1932 in Grand Rapids Michigan and was a distributor of Facit calculators from Sweden. The brand still exists today as a manufacturer of precision aircraft instruments.