Slide Rule
I can't imagine how a vernier could be set up for the non-linear scales.
My great uncle's 20 inch rule cut the uncertainty in half compared to the common size.
I've seen an antique multi-section slide rule with the sections mounted on a reel, claimed to be equivalent to a 40-ft or so long slide rule. Very awkward and probably hard to keep the multiple segments in calibration. Maybe this model found here https://www.sliderulemuseum.com/Rarities.htm
But, but, the magic trig numbers were to five places after the decimal in the handy dandy trig function tables in the big book. I had a professor who claimed he could read his stick in a case hanging from his belt to five places.
@bill93 I didn't really think about it, someone claimed in a YouTube comment that some had verniers to gain a significant digit but you are right, don't know how that would work.
This got started because YouTube started suggesting old Mechanical Adding Machine (some could multiply and divide too) videos so I got interested in them. I had no idea what a huge variety of machines were available. Then I saw a few slide rule videos.
I could buy a mechanical machine, they are pretty cheap if one is nearby but they are often frozen because the old lubricants harden so they need to be freed up, cleaned and then oiled with the correct oil. Then I thought I have my Dad's engineering slide rule so I could use it for free, no need to try to find a machine then play mechanic trying to get it to work.
To effectively use a machine I would need a book of tables, have 2 or 3 books of various tables in my downtown office but I spend very little time in there.
Nice Museum! I believe the green instrument is a Wild RK1 alidade for Plane Table work. Rarely seen!
@MightyMoe the military still did some when I was in and agency. Wild T-0. But they had become very limited on doing compass rose. I think if I was tasked to do one I would have to re learn as we did so few and I just can’t get the brain to recall everything anymore. I got out in 2005. So not that long ago.
Magnesium?! Why on Earth...?
During more than 50 years, I had not heard of the Bowman Brain. When I broke in '72, the Kurta and trig tables were the standard in the field in my area. I only remember a Compucorp handheld that others were using. seemed clunky vs the HP35.
When the HP35 became available in late 1972, that changed everything. I had an HP55 with an external card reader. $400 in 1974.
The slide rule was a segment of a math class in junior high, but was never something I used in surveying.
You learn something every day, right?
JA, PLS, SoCal
I don't know if I've seen a slide rule before, I must have, but if I did I'm pretty sure I didn't know what I was looking at. I've seen a curta before but I didn't know that that's what they were called.
