Thursday, 2 June 2011

Readers under 45 look away now

Many of you over about 45 years of age will recognise the object below as a British Thornton slide rule - the tool we used in school immediately prior to the introduction of the Casio electronic calculator to do advanced maths. Calculus, logs, cosines and the rest were figured by lining up points on the sliding centre bar and reading the answering figure from the cursor hairline. You can buy them on eBay for under a tenner. No batteries, no electronics and therefore immune from EM radiation, showerproof and therefore a useful aid in the boatyard, it earns its place alongside the kerosene pressure lanterns, the Cat 'C' first aid kit and the British Berkefeld water filter in the land grab-bag. 

Except you may also need your reading glasses or a small magnifier these days to see the tiny figures. Grrr. 


Pavlov's Cat said...

Yep still got mine

Pavlov's Cat 45 3/4

APL said...

I have two, the oldest my fathers made in Bavaria by A.W. Faber, the other a plastic jobbie which, I can't find just now.

Also a pair of British Thornton dividers and compass.

Sue said...

I still have one too. Believe or not (I'm 50ish), I actually got shown how to calculate on an abacus when I first started infant school. We even printed a weekly leaflet and were taught how to typeset on an old fashioned printer (packing metal letters into a frame with wooden wedges to keep them in place).

Pete said...

When I started work in 1966 we actually used these as they were more accurate than flat slide rules:

Wish I'd kept mine now !

I also remember our first electronic calculator which was a mains powered 4 function thing the size and weight of a couple of housebricks. It cost just under £400 and was locked away each evening.

Elby the Beserk said...

Love them. Used to go into Miller's the Stationers in Cambridge, as a schoolbiy there, just to stare at them.

Got a Froude's slide rule by chance a while back. Sold it on to someone, but it was rather fine - wood as well.

Exercise your slide rule lust here

Elby the Beserk said...

Went to the USSR in 1968. Shopkeepers used abacuses there for all their calculations.

Blue Eyes said...

Although we had graphic calculators by the time we got to A Level we were still taught to use log tables and stuff. The exam board issued a very fetching green booklet with all sorts of useful data.

Anonymous said...

All thanks to Pierre Vernier (1580-1637) who invented a movable graduated scale for obtaining fractional parts of subdivisions on a fixed main scale.

I didn't use a slide rule cos I was too fick* at school - my sister has the brains in our family so she had one. She took A-Level maths (1970) and her marks were in the top one percentile for England that year.

*I do use a Vernier Calliper cos I is a precision engineering craftsman - dying breed.


Weekend Yachtsman said...

Beautiful thing.

At school we also had mechanical calculators. I believe they were Swedish; you dialled up various things and then turned a handle a bit like a bus conductor's ticket machine, and somehow it showed the answer. They could do multiplication but (I think) not division. No doubt they cost a bomb; as did, to be fair, the first electronic calculators.

We used to spend whole afternoons playing with them, so amazing did we find them.

Ou sont les neiges d'antan...

opsimath said...

My fiancee bought me a King Otis hand-held rotary calculator for my HNC finals in 1970. It was a fantastic piece of kit and was accurate, if your eyes were sharp enough, to a good 3 places.

Sadly it was lost in a move some years ago, but I'll never forget it; if I remember rightly, it cost about £4/10/0 - a sizeable sum back then.

Wish I'd still got it - thanks for the memory-jog!

SimonF said...

One of my electronics lecturers had a huge one at the front of lab which he could whizz up and down with amazing speed and come up with answers faster and just as accurately as those with early calculators, especially those that used Polish Notation.

Although reasonably accurate he used to refer to it as a guessing stick, which is about right but usually good enough for everyday work. It really narks me whenever I here football commentators describe a pass as having slide rule accuracy grrr

Anonymous said...

I can just about remember these along with log tables

Nigel Sedgwick said...

I remember owning one, and also that being a distinct rarity at my school. They were allowed in exams (A-levels 1971) and, in those days, permission involved just saying "I'm going to take it in and have checked it is permitted."

But why must those under 45 turn away? There is nothing wrong with technology moving from currency to history.

Does everyone know the slide-rule 'story' about Montgomery and the artillery officer?

Best regards
Nigel Sedgwick

Anonymous said...

You can do calculas on a slide rule?

One of the good things about a slide rule is that it encouraged one to do orders of magnitude, as well as the approximate answer in the head. This is a good excercise, as at times, a computer or calculator gets it wrong.

Anonymous said...

Like all great inventions, simple, not many moving parts, accurate and so efficacious, great stuff!
We had a chem' master, who delighted in racing, using his slide rule [in blackboard calculations] agin all comers!!

Anonymous said...

What is a Berkefeld water filter?

Wildgoose said...

I still have mine, (and I inherited my grandfather's also).

I remember that only one other lad in my year (other than myself) had one and knew how to use it. We were probably the last in my school to do so. (I think we were the last year to have log books as well).

I'm 46 by the way.

opinion prole said...

I graduated in Mech Eng in 1966 and I still have the slide rule, and the steam tables, so there.
First office job I had we used a mechanical desk calculator where you set the numbers with keys and cranked the handle. It was labelled FACIT and you can guess what we called it.

Anonymous said...

I am only 36, but I have my grandfather's one up in the loft. I can still (just) about remember how to use it as well, as he did show me how it worked.