I recently found out what a vernier is. Here’s Wikipedia’s explanation of how it works: Vernier - Wikipedia and Here’s a site that lets you play with a Java animated version: http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=52. A very nifty concept in my opinion. It made me wonder about all the pre-electronic things like slide rules, Curta calculators , and other things that were used in the pre-digital age that are rapidly being forgotten. Has anyone created a web site or published a book devoted to things like this? Sort of like a science-fiction scenerio of “if you had to operate in an EMP enviroment without computers, what could you use?”.
Vernier calipers are still in use, and still made. I hate using them because they’re too hard to read, and much prefer dial or digital calipers as they don’t strain my eyes.
How about Lissajous figures? Lissajous curve - Wikipedia
The best I can figure out, their only use is to look cool in old SciFi films.
Well, there’s this page for Curta calculators.
And I learned how to use a sextant a while ago, so there’s still a few people around who know how. There are even companies that still make them, although good ones are expensive. Check the wikipedia page for examples. And the micrometer drum works just like a vernier.
Something “between” analog and digital:
Before word-processing was done on computers, it was done on a machine called the Frieden Flexowriter. Data wasn’t stored on magnetic media, but rather on punched tape.
The original draft was manually typed on the electronic typewriter, which punched a line of holes across a band of tape. Each character (or space, or carriage return, or uppercase) was one line. The tape could be fed through the machine to automatically produce an exact copy, or it could be fed through while also punching a new tape, and stopping at the points where modifications were wanted. Then the second tape was the new draft, with changes.
So it was digital in that each character was part of a binary string (hole or no hole), but it wasn’t “digital” in that it didn’t use magnetic storage, and there was no “CPU.”
The flexowriter was used mostly for communications but some used it for “off-line” purposes such as document preparation and what we now call “mail merge.” Punched tape in general was used for various kinds of automated machinery commands, and later for computer data storage. It helped lead to the development of ASCII.
Why not go all the way and use a mechanical PC :eek:
Like Tuckerfan says, verniers are still very much in use.
In a weird tangent, more and more measurement devices that have nothing to do with verniers are getting called verniers, as if the word means “fine and precise and desireable” rather than referring to the clever trick of getting scales with slightly different spacing to display additional resolution by lining up particular scale marks.
This past year, I upgraded from a builder’s transit to a digital electronic total station, to use in my historic ruins surveying hobby. While the vernier scale is a clever idea, let me highlight for you how difficult it can be to use. My old transit uses a vernier scale to read the azimuth angle. The main scale doesn’t read 0 to 360, it reads 0 to 90 to 0 to 90 to 0. That means that half the time you are reading clockwise=increasing and half the time clockwise=decreasing. They therefore put vernier scale markings running both directions from the 0 reference mark (which if you will think about it isn’t even strictly necessary). Moreover, while the main scale is labeled every 10 degrees and has ticks for every 1 degree, the vernier scale is labeled every 15 minutes and has ticks for every 5 minutes. To top it all off, the scales are much to fine to read with the naked eye, and so you have to use a magnifier - but the scales point up, so you have to get high enough to bring it all into focus, not an easy job when you also have to get low enough to sight through the eyepiece. Unless of course you add a mirror to this setup…
Time to salute the old Torpedo Data Computer, especially the US Navy version. Not only did it allow submarines to aim their torpedoes correctly, combining various input data to calculate an optimum firing angle (and actually transmitting the resultant data to the torpedoes), but it also kept track of the relative positions of submarine and target(s) during times when no observations could be made.
All analogue.
I was trained on “real” verniers - the ones where you had to align the lines to get a reading. Moving to dial calipers was a big step, but I still use them, 35 years later. Same with “analog” micrometers. To me, digital is just wrong.
But that’s just my opinion.
I also started early NC work using punched tape and a flexowriter. In my first programming class, we were required to be able to read the tape by looking at it.
How about a hatchet planimeter?
It’s for measuring the area of a figure drawn on paper.
You take a length of wire, bend a little bit at both ends in the same direction by 90 degrees, then hammer one of the ends so it is thin and sharp, like the blade of a hatchet with the rest of the wire as its handle.
Then, you place this thing on the paper, with the un-flattened end somewhere on the edge of the figure, and the flattened end resting on the paper out beyond the figure somewhere.
You mark where the flattened end is.
Now, you trace the figure with the unflattened end, returning to your starting point. While you do so, the flattened end is sliding along the paper, guided by its hatchet edge, meanwhile angling according to the orientation of the wire. When you are finished, the flattened end is displaced perpendicularly to its sharp edge.
This displacement is proportional to the area of the figure you traced.
Because for most people “computer” is synonymous with microprocessor, the average person doesn’t know that Analog Computers existed. Some of them are mindblowing, like that second picture on the wiki page.
Also, what did they call those mercury tubes that they used to store data way back?
From
A mercury delay line is a tube filled with mercury, with a piezo-electric crystal at each end. Piezo-electric crystals, such as quartz, have the special property that they expand or contract when the electrical voltage across the crystal faces is changed. Conversley, they generate a change in electrical voltage when they are deformed. So when a series of electrical pulses representing binary data is applied to the transmitting crystal at one end of the mercury tube, it is transformed into corresponding mechanical pressure waves. The waves travel through the mercury until they hit the receiving crystal at the far end of the tube, where the crystal transforms the mechanical vibrations back into the original electrical pulses.
Mercury delay lines had been developed for data storage in radar applications. Although far from ideal, they were an available form of computer memory around which a computer could be designed. Computers using mercury delay lines included the ACE computer developed at the National Physical Laboratory, Teddington, and its successor, the English Electric DEUCE.
Hours of fun playing with a Virtual Curta Calculator!
(Requires Flash 6)
One thing my parents discovered cleaning out their house was a “pocket calculator”, somewhat similar to this one, that my mother bought after she married my father to help her balance the checkbook. It worked by using the stylus on the side to slide the different numbers into position.
Say you wanted to add 832 to 624. Here’s how it worked as I recall: first, you’d put the stylus in the corresponding numbered hole of the proper column and drag it down for each digit, until you see “832” in the top “display”. Then, to add your numbers, you’d first put your stylus in the “4” hole and drag it to the bottom, where it’d stop, and you’d have a “6” on the display. Same thing with adding the 2 to the 3. On to the hundreds place where you’re adding 6 to the 8. But you’ll find that, when you put your stylus in the “6” slot, you can’t move the slide all the way to the bottom. In that case, you instead push the stylus to the top of the column (which places a “4” in the hundreds place on the display), slide your stylus to the left (you’ll note that the slots for the sliders are wider at the top, so you can slide the stylus over one place), and notch it down one, putting a “1” in the thousands place. The model at the above link appears to allow subtraction on the same side; on the model my mother had, you had to put in the first number on the front and flip the calculator over to do the subtraction.
The “clear” function, by the way, is that thin metal bar across the top. Pull that straight up, and all columns were slid back to zero.
I was fascinated by that calculator; it was like something from another world. Wonder where I put it…
On the Univac I they were called acoustic delay lines.
I never programmed the beast, but I was friends with several who did. There were 1000 numbered memory location (the machine was entirely binary coded decimal) each holding 72 bits (2 words per location, each made up of 6 bytes of 6 bits each). At any given time 100 locations, all the ones with the same last digit of its address, were circulating in the vacuum tubes that made up the machine and the other 900 were traversing the mercury drums as acoustic signals. To program for maximum, you had to calculate which memory would be coming out of the mercury drum when your computation finished and stored there. This was called minimum latency coding. The MTBF was about 5 minutes since the vacuum tubes were constantly burning out. I think machines of this type would have been the zenith of digital computing had transistors not arrived.
My father had one of those. He regularly dealt in 6-figure numbers and used it to check his math.
My wife’s grandmother, who came from Japan, preferred a soroban.
Verniers are a pretty accurate way of measuring distance. They’re used in making semiconductors and can hold alignment down to a repeatability of a few nanometers or less (The actual measuring is done through digital sampling of laser light that has been relected and scattered by the vernier.)
It may be easier to quantify things through digital methods but the world as we experience it is still analog.
You’re not thinking of an Interferometer, are you?
IIRC, the one on my old MEBES had a resolution of 1/10 wavelength of HeNe light.