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Jaap Scherphuis

@jaapsch.net

Mathematician, likes mechanical calculators, twisty puzzles, the Psion II, and tiling patterns. See https://www.jaapsch.net

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Latest posts by Jaap Scherphuis @jaapsch.net

The 15th Anniversary Escape Pod book, but the typefaces makes it look a bit like ESCAPE POO.

The 15th Anniversary Escape Pod book, but the typefaces makes it look a bit like ESCAPE POO.

I think one of these books would benefit from a different font.

06.03.2026 14:19 πŸ‘ 134 πŸ” 14 πŸ’¬ 12 πŸ“Œ 0

I prefer Escape Poo to the non-escape kind.

06.03.2026 14:28 πŸ‘ 4 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Preview
Jacques de Vaucanson - Wikipedia

The company Ateliers Vaucanson was named after an 18th century mechanical wizard who made industrial machinery, but is better remembered by his automata. The Digesting Duck no longer exists but has almost gained mythical status in the retelling of what it could do.

en.wikipedia.org/wiki/Jacques...

23.02.2026 12:10 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Vaucanson AVA13 mechanical calculator
Vaucanson AVA13 mechanical calculator YouTube video by Jaap Scherphuis

I just posted a video of the Vaucanson AVA13 mechanical calculator. You don’t see these very often outside France. This one was used in the 1950s by the Dutch Royal Army at the barracks in Schoonhoven (havenkazerne). (1/2)

youtu.be/16-o-QOOnvE

23.02.2026 12:10 πŸ‘ 3 πŸ” 1 πŸ’¬ 1 πŸ“Œ 0

Apparently it is based on that, but then the labels generation could do with some improvement

09.02.2026 13:40 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Apparently I’m a Progressive North American Creative Professional. That label seems to be in intergalactic space, somewhat away from clusters. It definitely can’t be based on the people I follow, or the few who follow me.

09.02.2026 13:37 πŸ‘ 0 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Reminds me of Garfield without Garfield

26.01.2026 11:05 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

That’s the whole point…

23.01.2026 10:32 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Quinn Quinn Whoo!

17.01.2026 16:26 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Finally made a video if this machine. It seems to be quite rare since I have not found any trace of it on the internet, no mentions at all, let alone pictures. The only info is the patents.

SchildkrΓΆt Minirechner 99
youtu.be/3su3Y6Kmzp8

12.01.2026 22:33 πŸ‘ 3 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Yes. Removing the added parts pretty much gives you the simpler model, but with some holes in. The variants without the automatic multiplication remained in production too so combined production was relatively simple.

12.01.2026 05:45 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

BTW, mine has an extra register which the ebay one doesn’t.

04.01.2026 00:36 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
The Rheinmetall SASL mechanical calculator
The Rheinmetall SASL mechanical calculator YouTube video by Jaap Scherphuis

The (Rhein)Metall Super Automat. It’s a large mechanical calculator with fully automatic division and multiplication. Very heavy so hard to lift even with those two handles.

youtu.be/r9_nLsXAWkw?...

04.01.2026 00:35 πŸ‘ 4 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

Happy new year!

31.12.2025 21:40 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Video thumbnail

Let’s see what happens…

31.12.2025 21:40 πŸ‘ 3 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Video thumbnail

It was too late to save the company - it was bought by Victor. The Electrowriter was considered the most valuable asset, more than the Comptometer calculators themselves.

The gif below shows some amazing footage of a pair of Electrowriters in action, from an office exhibition from 1966. (2/2)

21.12.2025 16:34 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
1959 ad for the Electrowriter by the Comptometer Corporation.

1959 ad for the Electrowriter by the Comptometer Corporation.

At the end of the 1950s the Comptometer Corporation (formerly Felt & Tarrant) was not doing well financially. They desperately needed a hit product, and came up with the Electrowriter. Two machines connected by a phone line, like a fax machines, but you could transmit live writing and drawing. (1/2)

21.12.2025 16:34 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Brunsviga Nova II mechanical calculator with a pinwheel mechanism.

Brunsviga Nova II mechanical calculator with a pinwheel mechanism.

The calculator illustrated in the ad is a slightly later version of this machine, a Brunsviga Nova II. This is amongst the first machines I added to my collection.

13.12.2025 22:12 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Sicher und schnell
errechnet LZ129 Hindenburg seinen kurs auf
Brunsviga Rechenmaschinen

Sicher und schnell errechnet LZ129 Hindenburg seinen kurs auf Brunsviga Rechenmaschinen

Awesome 1936 ad for the Brunsviga mechanical calculator, which apparently was used aboard the Hindenburg zeppelin to calculate its course. The vessel flew for only 14 months till its disastrous crash in May 1937.

13.12.2025 21:39 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

I’ve seen one on eBay once, but it is very rare. I’ve also seen the microphone with the control buttons once or twice, and a spare tape loop, but I don’t search for Comptometer stuff as often as I used to.

06.12.2025 06:17 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Page from the instruction leaflet for the Comptometer dictation machine. It has a list of 10 commandments for good dictation:

1. I will dictate clearly and distinctly and spell out unusual names and places.

2. I will talk to my secretary through the unit, not to the machine.

3. In an unusually noisy room I will make an extra effort to speak more distinctly into the microphone.

4. When I pause during dictation I will remember to release the microphone switch so that my secretary will be able to judge the length of the letter by looking at the recording log.

5. I will eliminate guesswork for my secretary by dictating punctuation and paragraphs.

If there are any notations, isolated P.S.'s, etc., I will make note of them on the recording log which I will use to identify each letter.

7. When an error or changes occur I will take full advantage of this unit's Erase-O-Matic belt and turn over Error-Free dictation to mmy secretary.

8. I will make my letters concise and conversational.

9. If cigars, chewing gum, etc. muffle my voice, I will abstain until my dictation is completed.

10. While noticing the blonde file clerk or other interesting distractions, I will try to remember to keep the microphone near my lips while my head rotates.

Page from the instruction leaflet for the Comptometer dictation machine. It has a list of 10 commandments for good dictation: 1. I will dictate clearly and distinctly and spell out unusual names and places. 2. I will talk to my secretary through the unit, not to the machine. 3. In an unusually noisy room I will make an extra effort to speak more distinctly into the microphone. 4. When I pause during dictation I will remember to release the microphone switch so that my secretary will be able to judge the length of the letter by looking at the recording log. 5. I will eliminate guesswork for my secretary by dictating punctuation and paragraphs. If there are any notations, isolated P.S.'s, etc., I will make note of them on the recording log which I will use to identify each letter. 7. When an error or changes occur I will take full advantage of this unit's Erase-O-Matic belt and turn over Error-Free dictation to mmy secretary. 8. I will make my letters concise and conversational. 9. If cigars, chewing gum, etc. muffle my voice, I will abstain until my dictation is completed. 10. While noticing the blonde file clerk or other interesting distractions, I will try to remember to keep the microphone near my lips while my head rotates.

The instruction leaflet has a list of 10 commandments for good dictation. Number 10 is ... of its time. Very Mad Men.

"10. While noticing the blonde file clerk or other interesting distractions, I will try to remember to keep the microphone near my lips while my head rotates." (3/3)

05.12.2025 23:30 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Another ad for the Comptometer dictation machine. It pictures a close up of a man speaking into a microphone, looking sideways very guiltily as if he is about to be caught by lieutenant Columbo.

Another ad for the Comptometer dictation machine. It pictures a close up of a man speaking into a microphone, looking sideways very guiltily as if he is about to be caught by lieutenant Columbo.

Here's another ad for this dictation machine. Doesn't he look very shifty...

The machine used a very wide short loop of Mylar recording tape, more like a cylinder, called the Erase-O-Matic belt. This allowed for quick seeking to any spot in the recording. (2/3)

05.12.2025 23:30 πŸ‘ 1 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
Advert from March 1956 for the Comptometer Commander, a dictation machine made by Felt & Tarrant.

Advert from March 1956 for the Comptometer Commander, a dictation machine made by Felt & Tarrant.

The Felt & Tarrant company made the Comptometer, a type of mechanical calculator that was in production from 1889 till about 1960.

In the 1950s they tried to expand to other products.

Here is an advert for their dictation machine. It was given the manly name, the "Comptometer Commander. (1/3)

05.12.2025 23:30 πŸ‘ 3 πŸ” 0 πŸ’¬ 2 πŸ“Œ 0

Just like Nashorn for a rhinoceros

04.12.2025 12:42 πŸ‘ 0 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
screenshot of an ebay listing of a burroughs class 5 adding machine. 

it has a grid of keys in 10 columns and 9 rows with a readout register below all the keys. the rows are labeled 1-9 with their 9s complement in smaller text.

normally the colors of the keys in each set of columns are the same, either black or white. the normal arrangement from right to left is 2 columns for fractions of 100 then the columns are grouped by 3s to match normal commas in numbers.

this adding machine has a checkerboard pattern except for the left most column which is all white because of a lack of black keys.

the worst part is the "keycaps" are not normally removable and you would need to spend hours on disassembly and reassembly. of course this pattern means you cannot quickly use the adding machine because the column colors help with accuracy

screenshot of an ebay listing of a burroughs class 5 adding machine. it has a grid of keys in 10 columns and 9 rows with a readout register below all the keys. the rows are labeled 1-9 with their 9s complement in smaller text. normally the colors of the keys in each set of columns are the same, either black or white. the normal arrangement from right to left is 2 columns for fractions of 100 then the columns are grouped by 3s to match normal commas in numbers. this adding machine has a checkerboard pattern except for the left most column which is all white because of a lack of black keys. the worst part is the "keycaps" are not normally removable and you would need to spend hours on disassembly and reassembly. of course this pattern means you cannot quickly use the adding machine because the column colors help with accuracy

what monster did this????

01.12.2025 02:59 πŸ‘ 8 πŸ” 2 πŸ’¬ 3 πŸ“Œ 0

This is just so that they could say Spinal Tap style that their machines were one better than the competitor.

01.12.2025 10:41 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0

You know, what really gets me is that they forgot two swap one pair near the top left.
There is one white column on the left side which reminds me of this fun fact: larger Burroughs 5 machines always have an odd number of columns (9/11/13) because they have one more than the Comptometer (8/10/12)

01.12.2025 10:41 πŸ‘ 2 πŸ” 0 πŸ’¬ 1 πŸ“Œ 0
β€œAre machines smarter than me?”
On the right is a line drawing if a distraught man cowering inside a box.
It is a 1949 ad for the Comptometer mechanical calculator.

β€œAre machines smarter than me?” On the right is a line drawing if a distraught man cowering inside a box. It is a 1949 ad for the Comptometer mechanical calculator.

β€œAre machines smarter than me?”

This 1949 ad for the Comptometer mechanical calculator discusses the question we are still struggling with now, and comes to the conclusion that grey matter beats any new-fangled machine.

25.11.2025 14:16 πŸ‘ 1 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

I saw this film at an afternoon showing one summer. I was the only one there. Sitting in the middle of the front row of an empty cinema, I saw Sam Neill sitting in the front row of an empty cinema watching himself on the screen, going mad and laughing hysterically. I almost did the same.

25.11.2025 05:14 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Interesting development! Btw, I had to use a VPN to read the linked article because they block EU visitors (due to not wanting to follow data protection regulations).

19.11.2025 16:11 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0