Significant digits in a float?

[Ian Kelly]

It also works if your starting point is (precisely) the north pole. I
believe that's the canonical answer to the riddle, since there are no
bears in Antarctica.

 

[Dennis Lee Bieber]

in a physics or chemistry class the recommended result is

1.1 * 2.2 => 2.4

More than recommended. In my physics class, if you put down more
significant digits than the input data justified, you got the problem
marked wrong.

(one reason slide-rules were acceptable for so long -- and even my high
school trig course only required slide-rule significance even though half
the class had scientific calculators [costing >$100, when a Sterling
slide-rule could still be had for <$10]) <G>

Sterling? Snort. K&E was the way to go.

Math teacher was selling them in my 10th grade... Actually I already
owned a Faber-Castell 57/22 "Business" ruler (which did NOT have the CF/DF
scales set for *PI) and a Pickett N-1010-ES Trig rule.

I've misplaced the Sterling, but I'm fairly sure it was a deci-trig
log-log model.

In the last 15-20 years I've added NIB versions of Faber-Castell 1/54
Darmstadt, Pickett N-803-ES Dual-Base Log-Log, Pickett Cleveland Institute
of Electronics N-515-T, and a pair of Sama&Etani/Concise circular pocket
rules (models 200 and 600).

Heh... I wonder if the VEs would have noticed the CIE rule had lots of
electronics formulas on the back, if I'd taken it to the exam session where
I passed both General and Amateur Extra tests. I couldn't take a calculator
-- all of mine were programmable. But the slide-rule I took was just about
as perplexing to the VEs.

 

[Chris Angelico]

It also works if your starting point is (precisely) the north pole. I
believe that's the canonical answer to the riddle, since there are no
bears in Antarctica.

Yeah but that's way too obvious! Anyway, it's rather hard to navigate
due south from the north pole. Which way do you go? How do you know
you're still going due south? Will the rocket even light in that
climate?

Important questions must be answered!

ChrisA

 

[Terry Reedy]

It also works if your starting point is (precisely) the north pole. I
believe that's the canonical answer to the riddle, since there are no
bears in Antarctica.

For the most part, there are no bears within a mile of the North Pole
either. "they are rare north of 88°" (ie, 140 miles from pole).
https://en.wikipedia.org/wiki/Polar_bears
They mostly hunt in or near open water, near the coastlines.

I find it amusing that someone noticed and posted an alternate,
non-canonical solution. How might a bear be near the south pole? As
long as we are being creative, suppose some jokester mounts a near
life-size stuffed black bear, made of cold-tolerant artificial
materials, near but not at the South Pole. The intent is to give fright
to naive newcomers. Someone walking in a radius 1/2pi circle about the
pole might easily see it.

 

[Mark H Harris]

Absolutely, snort. I still have my K&E (Keuffel & Esser Co. N.Y.);
made of wood... (when ships were wood, and men were steel, and sheep ran
scared) ... to get to the S L T scales I have to pull the slide out
(turn it over) and reinsert it. You're right, the CF and DF scales are
missing, but the A B scales have the π symbol where it should be (more
or less). Mine is the 4058 C model, and you're right... has maths
equivalents and conversions printed on the back...

I've misplaced the Sterling, but I'm fairly sure it was a deci-trig
log-log model.

My high school '74 was the last class to learn the slide-rule using
the Sterling (we paid a deposit to use the school's). I returned my
Sterling to the teacher at year-end and got my deposit back. They are
all probably in an old card-board box in the basement. I should ask.

In the last 15-20 years I've added NIB versions of Faber-Castell 1/54
Darmstadt, Pickett N-803-ES Dual-Base Log-Log, Pickett Cleveland Institute
of Electronics N-515-T, and a pair of Sama&Etani/Concise circular pocket
rules (models 200 and 600).

I received my Pickett Model N4-T Vector-Type Log Log Dual-Base Speed
Rule as a graduation | birthday gift... off to college with a leather
cased slip stick hanging from my belt (I was invincable). Mine had the
CF/m DF/m scales also -- folded at 2.3, the loge of 10 with π where it
should be (more or less). Copyright 1959... that baby was the king of
slide rules... I pull it out from time to time, just for warm feelings.

Heh... I wonder if the VEs would have noticed the CIE rule had lots of
electronics formulas on the back, if I'd taken it to the exam session where
I passed both General and Amateur Extra tests. I couldn't take a calculator
-- all of mine were programmable. But the slide-rule I took was just about
as perplexing to the VEs.

I carried my slide rule to my general class exam as well. The VE
inspected it to be sure that certain stuff was not written in pencil
between the scales! True story. Its not required today, of course, but I
can still send/receive at 20 wpm. <sigh>

marcus W0MHH
'73

 

[Paul Rubin]

I received my Pickett Model N4-T Vector-Type Log Log Dual-Base
Speed Rule as a graduation | birthday gift...

There is a nice Javascript simulation of the N4-ES here:

http://www.antiquark.com/sliderule/sim/n4es/virtual-n4es.html

Some other models are also on that site.

 

[Mark H Harris]

There is a nice Javascript simulation of the N4-ES here:

http://www.antiquark.com/sliderule/sim/n4es/virtual-n4es.html

Thank you!

The N4-ES and the N4-T (mine) are essentially the same rule. The N4-ES
on the site is yellow (mine is white) and the site rule indicates Picket
& Eckel Inc. (that's where the E comes from) Also the the ES states
Chicage Ill USA where the T states Made in USA.

The only technical difference is the T scale (which is folded-expanded
on both). On the ES the T scale is listed only once in the margin. On
the N4-T the T scale is listed 'twice'!-- once for each part of the
fold. Well, that gives (2) scales instead of one --for T... increasing
the number of scales on the rule from 34 to 35... if I'm counting right.
Which makes the N4-T more valuable... supposedly. I don't plan are
parting with it... till I croak, then my son (who is studying
engineering this fall) will inherit it... heh he won't have a clue
what to do with it !

The simulated rule on the site above is fabulous... especially if viewed
from a large wide LED. ... simply fabulouso/



marcus

 

[Gregory Ewing]

For the most part, there are no bears within a mile of the North Pole
either. "they are rare north of 88°" (ie, 140 miles from pole).
https://en.wikipedia.org/wiki/Polar_bears
They mostly hunt in or near open water, near the coastlines.

The way things are going, the coastline might be
within a mile of the north pole quite soon.

 

[Vlastimil Brom]

Yeah but that's way too obvious! Anyway, it's rather hard to navigate
due south from the north pole. Which way do you go? How do you know
you're still going due south? Will the rocket even light in that
climate?

Important questions must be answered!

ChrisA

Well, after having been following the discussion, I couldn't resist
but post the relevant sketch from the famous Czech play "The Conquest
of the North Pole by the Czech Karel Němec on 5th April 1909" by Jara
Cimrman [as "dicovered" and presented by Z. Sverak and L. Smoljak]
(translated by Craig Cravens)

http://jaracimrman.files.wordpress.com/2010/04/north_pole.pdf (pp. 38-39)

============

Teacher: And now, friends, I’d like to draw your attention to a
certain geographical
peculiarity. If I stand next to the chief and step off in any
direction, I always go south.
Pharmacist: No!
Teacher: Yes, yes! Watch! (stands next to the chief and steps off.)
I’m going south.
(He returns and sets off in another direction.) And now I’m going
south again. And now
—once again south.
Pharmacist: That’s unbelievable!
Teacher: Hold on, you haven’t seen anything yet. Richard, stand here
with your back to
the chief. And now both of you, step forward.
(Schwarzenegger and the chief, with their backs to each other, step forward..)
Did you see that? They’re both going south!
Pharmacist: That’s really something else!
Teacher: And I’ve saved the best for last. Now, you’ll really see
something. Vojtěch,
mark the Pole with an X and step aside.
(Vojtěch obeys. The teacher sets off toward the mark.)
Watch this. I’m going north (he crosses the mark and continues
walking) and now I’m
going south! And now back: north … and now south.
Pharmacist: That’s impossible!
Teacher: Try it yourself.
Pharmacist: This I’ve got to see. (He walks towards the pole and
the<m> moment he
crosses it his face lights up with joy.) Wow! Friends, this was worth
it! On the verge of
death from hypothermia, from hunger, and from exhaustion, but it was worth it!


=============

regards,
vbr

 

[Roy Smith]

Absolutely, snort. I still have my K&E (Keuffel & Esser Co. N.Y.);
made of wood... (when ships were wood, and men were steel, and sheep ran
scared) ... to get to the S L T scales I have to pull the slide out
(turn it over) and reinsert it. You're right, the CF and DF scales are
missing, but the A B scales have the π symbol where it should be (more
or less). Mine is the 4058 C model, and you're right... has maths
equivalents and conversions printed on the back...

For those who have no idea what we're talking about, take a look at
http://www.ted.com/talks/clifford_stoll_on_everything. If you just want
to see what you do with a slide rule, fast forward to 14:20, but you
really owe it to yourself to invest the 18 minutes to watch the whole
thing.

 

[emile]

I'm pretty sure there are places in London like that. At least that's
what it seemed like to somebody from the midwestern US where the
streets are layed out on a grid.

I was going to bring up London, but as I recall from my brief visit
there, I wasn't sure you could go one mile straight in any direction.



Emile

 

[Adam Funk]

Wow. It's amazing how writing something down, wrongly (I originally had north and south reversed), correcting it,
letting some time pass (enough to post the message so one can be properly embarrassed , and then rereading it later
can make something so much clearer!

It's amazing how big a subthread appeared in response to a gag that I
think I got from a Car Talk puzzler.


--
A recent study conducted by Harvard University found that the average
American walks about 900 miles a year. Another study by the AMA found
that Americans drink, on average, 22 gallons of alcohol a year. This
means, on average, Americans get about 41 miles to the gallon.
http://www.cartalk.com/content/average-americans-mpg

 

[Adam Funk]

(one reason slide-rules were acceptable for so long -- and even my high
school trig course only required slide-rule significance even though half
the class had scientific calculators [costing >$100, when a Sterling
slide-rule could still be had for <$10]) <G>

Sterling? Snort. K&E was the way to go.

Math teacher was selling them in my 10th grade... Actually I already
owned a Faber-Castell 57/22 "Business" ruler (which did NOT have the CF/DF
scales set for *PI) and a Pickett N-1010-ES Trig rule.

What does a "business" slide-rule do? Depreciation?

 

[Adam Funk]

For the most part, there are no bears within a mile of the North Pole
either. "they are rare north of 88°" (ie, 140 miles from pole).
https://en.wikipedia.org/wiki/Polar_bears
They mostly hunt in or near open water, near the coastlines.

I find it amusing that someone noticed and posted an alternate,
non-canonical solution. How might a bear be near the south pole? As
long as we are being creative, suppose some jokester mounts a near
life-size stuffed black bear, made of cold-tolerant artificial
materials, near but not at the South Pole. The intent is to give fright
to naive newcomers. Someone walking in a radius 1/2pi circle about the
pole might easily see it.

OK, change bear to bird & the question to "What kind of bird is it?"

 

[Adam Funk]

On 05/01/2014 05:56 AM, Roy Smith wrote:

Anyone (besides me) ever seen a cylindrical slide rule? I have one -- unfortunately misplaced
at the moment. :-(

The scales were helical around a cylinder giving (it was claimed) to be the equivalent of a
five-foot rule. But that still only gave one additional significant digit. Only two scales,
however, which limited its use to multiply/divide and logs. But interesting.

I have a "circular" (really spiral) slide rule that I inherited from
my grandfather.

http://www.ducksburg.com/atlas_slide_rule/

One of my uncles told me that he took it (or a similar model) to
university (ca. 1960, I guess) & got an F on a calculus test because
his answers were too accurate & precise to be honest. He went to the
professor's office, showed him the circular slide rule, & got an A.

 

[Mark Lawrence]

OK, change bear to bird & the question to "What kind of bird is it?"

A buffalo with an aqualung possibly?

 

[Dennis Lee Bieber]

My high school '74 was the last class to learn the slide-rule using
the Sterling (we paid a deposit to use the school's). I returned my
Sterling to the teacher at year-end and got my deposit back. They are
all probably in an old card-board box in the basement. I should ask.

Since calculators had started to appear, I never did get formal
training in slide-rules. The LL scales still require me to glance at a
guide book...

I received my Pickett Model N4-T Vector-Type Log Log Dual-Base Speed
Rule as a graduation | birthday gift... off to college with a leather
cased slip stick hanging from my belt (I was invincable). Mine had the

Strangely, out of the three Picketts I now own, only the CIE had the
belt hook included.

CF/m DF/m scales also -- folded at 2.3, the loge of 10 with ? where it
should be (more or less). Copyright 1959... that baby was the king of

Interesting -- I've not encountered those scales.

I carried my slide rule to my general class exam as well. The VE
inspected it to be sure that certain stuff was not written in pencil
between the scales! True story. Its not required today, of course, but I
can still send/receive at 20 wpm. <sigh>

Whereas I started as a "no-good" Tech. It was the dropping of the code
requirement that encouraged me to try for the higher ratings. After all,
using a TS-570 just for 6m is rather limiting <G> [and even that was
difficult -- for a few months I had a mass PVC piping straddling a fence
supporting a pair of 6m HamSticks as a dipole... Until the apartment
manager complained.

Many moons ago, I could take Gregg shorthand at 100WPM <G> [but my
typing speed was only a slow 30WPM]


I regret that I never risked the $35 dollars when my college bookstore
was closing out the slide-rule display. They had the top Post bamboo
laminate rule at half price. At the time I'd bought an HP-25 calculator
[they phased out the HP brand a year or two later -- apparently RPN was too
confusing].

And, in a side comment, I once corrected a bookstore that had filed
Asimov's "Easy Introduction to the Slide Rule" under Science Fiction.

 

[Dennis Lee Bieber]

Thank you!

The N4-ES and the N4-T (mine) are essentially the same rule. The N4-ES
on the site is yellow (mine is white) and the site rule indicates Picket
& Eckel Inc. (that's where the E comes from) Also the the ES states
Chicage Ill USA where the T states Made in USA.

ES was for "Eye-Saver" -- the yellow background vs the bright white of
the other models.

For the audience who might be interested...
http://www.sphere.bc.ca/test/sruniverse.html
(The N515T is available for $95)

 

[Dennis Lee Bieber]

(one reason slide-rules were acceptable for so long -- and even my high
school trig course only required slide-rule significance even though half
the class had scientific calculators [costing >$100, when a Sterling
slide-rule could still be had for <$10]) <G>

Sterling? Snort. K&E was the way to go.

Math teacher was selling them in my 10th grade... Actually I already
owned a Faber-Castell 57/22 "Business" ruler (which did NOT have the CF/DF
scales set for *PI) and a Pickett N-1010-ES Trig rule.

What does a "business" slide-rule do? Depreciation?

Special markers for: dozen, gross; a scale for "non-metric measures" to
metric equivalents -- US Bushel, UK ("brit") bushel, US gallon, UK gallon,
short and long tons, a few Russian units, "Pud" and "R.t." which appear to
map to cubic inch and cubic foot; markings for % (discount and mark-up)

And a scheme for simple interest calculations (which may explain why
the CF/DF scales are longer than the C/D scales): "Move the main cursor
line over the principal on scale DF -- the principal must be taken only on
scale DF -- set the rate per cent on the scale CI, under the short cursor
line, and read the interest on the scale DF or D in line with the number of
days on the scale CF or C." {yes, just to the left of the normal cursor is
a short line only over the inverted C scale}

 

[Mark H Harris]

ES was for "Eye-Saver" -- the yellow background vs the bright white of
the other models.

Actually, I think you're right. I never used the a yellow rule, but
I will say that my N4-T never caused me any eye-strain (but I was
younger then).

The N4-T was a flat white also... very easy to read. I really don't
know what all the 'yellow' hype was all about.