Unofficial Christ's Hospital Forum

I am researching the development of handheld/desktop calculators and would be grateful for any help on an unusual mechanical device I remember being used by some boys at Housie during my time there - 1948-1955. I have searched Google but cannot find it, but a keyword would help.
It fitted into the hand and the frame was made of metal and was quite thin. There were a series of vertical sliders, each with holes numbered 0-9. It was operated by a stylus which was inserted into the appropriate hole and then moved (I think) downwards. If the resulting figure exceeded 9 the stylus was then used to track sideways to the next column. As you can see, my memory is a bit hazy, but, hey, it was a long time ago!
As I recall, it was quite expensive so only a few people had one.
I emphasis that it was entirely mechanical (handraulic, as they say), there was no question of electrical operation.
Any help gratefully received,
David

It sounds something like a development of an abacus, but I can’t say any more than that.

If you have ever seen someone using an abacus skilfully it is surprising how quickly they can do it, and, of course, get the right answer. Even more surprising is seeing someone make the same movements without a physical abacus and still get the right answer!

Foureyes wrote: Sat Aug 21, 2021 5:22 pm I am researching the development of handheld/desktop calculators and would be grateful for any help on an unusual mechanical device I remember being used by some boys at Housie during my time there - 1948-1955. I have searched Google but cannot find it, but a keyword would help.
It fitted into the hand and the frame was made of metal and was quite thin. There were a series of vertical sliders, each with holes numbered 0-9. It was operated by a stylus which was inserted into the appropriate hole and then moved (I think) downwards. If the resulting figure exceeded 9 the stylus was then used to track sideways to the next column. As you can see, my memory is a bit hazy, but, hey, it was a long time ago!
As I recall, it was quite expensive so only a few people had one.
I emphasis that it was entirely mechanical (handraulic, as they say), there was no question of electrical operation.
Any help gratefully received,
David

I owned one of these, though a bit later than you described. It worked just as you said. This link isn’t exactly the same, but pretty close.
https://www.mercari.com/us/item/m126981 ... 3cQAvD_BwE

Mike,
Many, many thanks. That is EXACTLY the information I was looking for.
I can remember being very envious of a contemporary who owned one of these.
David

Katharine,
A good guess concerning the abacus, but as LongGone has shewn this little machine had a different genesis.
But I do agree with you about the speed of skilled abacus operators. I well remember the Chinese shopkeepers in places such as Change Alley in Singapore who were really, really fast. When they went clickety-click (etc) on their abacus and then said, "that's a special price for you, Tuan, twenty-five dollars thirty" it was impossible for the bewildered Brit to argue because he or she had absolutely no idea how the calculation had been made.
David

Foureyes wrote: Sat Aug 21, 2021 5:22 pm I am researching the development of handheld/desktop calculators and would be grateful for any help on an unusual mechanical device I remember being used by some boys at Housie during my time there - 1948-1955. I have searched Google but cannot find it, but a keyword would help.
It fitted into the hand and the frame was made of metal and was quite thin. There were a series of vertical sliders, each with holes numbered 0-9. It was operated by a stylus which was inserted into the appropriate hole and then moved (I think) downwards. If the resulting figure exceeded 9 the stylus was then used to track sideways to the next column. As you can see, my memory is a bit hazy, but, hey, it was a long time ago!
As I recall, it was quite expensive so only a few people had one.
I emphasis that it was entirely mechanical (handraulic, as they say), there was no question of electrical operation.
Any help gratefully received,
David

Damn - I had one of these until quite recently but I think I must have thrown it out when I last moved house (2011). It was exactly as you describe it and was, I think, known as an 'addiator'. The key word to include when searching is probably 'mechanical'. This website may help: http://www.vintagecalculators.com/html/ ... ators.html

Foureyes wrote: Sun Aug 22, 2021 5:47 am I well remember the Chinese shopkeepers in places such as Change Alley in Singapore who were really, really fast. When they went clickety-click (etc) on their abacus and then said, "that's a special price for you, Tuan, twenty-five dollars thirty" it was impossible for the bewildered Brit to argue because he or she had absolutely no idea how the calculation had been made.
David

... or in Bugis Street perhaps?

During two tours in Singapore I never went near Bugis Street - not even once out of curiosity!!
David

Katharine wrote: Sat Aug 21, 2021 9:53 pm It sounds something like a development of an abacus, but I can’t say any more than that.

If you have ever seen someone using an abacus skilfully it is surprising how quickly they can do it, and, of course, get the right answer. Even more surprising is seeing someone make the same movements without a physical abacus and still get the right answer!

I suspect that you saw Mrs Macarian's pupils on Blue Peter. The primary school pupils were using the implements but those in their first year at secondary school just used fingers. Her lessons were discontinued because the school could not afford the one lesson per week time. They were using Sorobans which are Japanese equivalent of the Chinese abacus but different in that the soroban works in units of five instead of ? ten. She taught me and my soroban is beside my desk alongside my ancient slide rule.

sejintenej wrote: Sun Aug 22, 2021 8:19 pm

Katharine wrote: Sat Aug 21, 2021 9:53 pm It sounds something like a development of an abacus, but I can’t say any more than that.

If you have ever seen someone using an abacus skilfully it is surprising how quickly they can do it, and, of course, get the right answer. Even more surprising is seeing someone make the same movements without a physical abacus and still get the right answer!

I suspect that you saw Mrs Macarian's pupils on Blue Peter. The primary school pupils were using the implements but those in their first year at secondary school just used fingers. Her lessons were discontinued because the school could not afford the one lesson per week time. They were using Sorobans which are Japanese equivalent of the Chinese abacus but different in that the soroban works in units of five instead of ? ten. She taught me and my soroban is beside my desk alongside my ancient slide rule.

No I did not see it on Blue Peter, I was actually thinking of pupils I have taught, both Chinese in Brunei and a Japanese girl in England - who may have been using a soroban. I was a long time advocate of a slide rule!

Katharine wrote: Mon Aug 23, 2021 5:51 pm I was a long time advocate of a slide rule!

Still have mine.
For a long time I opposed the use of calculators in schools as GIGO. If you have no idea of the answer, how do you know if the calculator is correct?
I taught my children long division as their primary school teacher in Amsterdam advocated the calculator.
Futile conversation. I was not impressed.

Two real advantages of a slide rule were that you had to make a rough estimate to decide where the decimal point was, and also you couldn’t get an answer with apparently six significant figures from a starting point with two or three sig figs.

Yes I’ve still got mine, correction both of mine. I had a 5” one for lower secondary teaching as well as the 10” for higher levels.

jhopgood wrote: Mon Aug 23, 2021 9:52 pm

Katharine wrote: Mon Aug 23, 2021 5:51 pm I was a long time advocate of a slide rule!

Still have mine.
For a long time I opposed the use of calculators in schools as GIGO. If you have no idea of the answer, how do you know if the calculator is correct?
I taught my children long division as their primary school teacher in Amsterdam advocated the calculator.
Futile conversation. I was not impressed.

I also learned long division and multiplication in primary school. When I went to CH aged 9 they never ever touched on those.
One of my professional exams a compulsory question was to work out various foreign exchange options using complicated exchange rates and big amounts. Of course each one had to be worked out to completion but the use of any type of calculator was banned. A right pig!!!

Have just found in loft my addiator piccolo-s green/grey painted metal with aluminium stylus in a green plastic case. Attached to my Aristo scholar slide rule by a well perished rubber band!!
Piccolo has two sections of 6 sliding columns marked addition(at the top)and subtraction (at the bottom).
Judging by the scuff marks it was well used in the era before calculators came into use. Addition / subtraction achieved by using stylus to pull or push sliding numerical scale on each column in turn, with carry overs achieved by a short slot at column top / bottom allowing stylus to move adjoining column up or down one numeral. Zeroing scales before new calculations achieved by pulling a sliding arm upwards from top and returning.
Now if only I can remember how the slide rule worked!! Also does anyone remember logarithmic tables?!! I remember being amazed that they came in handy in at boat navigation evening classes shortly after I left CH. But long since consigned to the bin.

pierre wrote: Fri Nov 01, 2024 3:01 pm Now if only I can remember how the slide rule worked!! Also does anyone remember logarithmic tables?!! I remember being amazed that they came in handy in at boat navigation evening classes shortly after I left CH. But long since consigned to the bin.

I’m sure there must be YouTube videos showing you how to use a slide rule! In essence you add two lengths to get the answer. Sorry I’m not good at writing descriptions how to do it! If you were sitting beside me I could show you

The last time I had to think for a nanosecond about logs was a few years ago. A friend, also a former Maths teacher and very close to me in age, called out to me across a room of youngsters that the key code for a cupboard was log pi. I dialled 4971 and opened it, one of the youngsters did ask what was going on!