1920 Comptometer Mechanical Calculator

this thing sitting here in front of me is 100 years old I doubt much of what I own now will be as functional in 100 years as this is now and this will probably still work then this is a Comptometer while technically an adding machine I feel that term really sells it short yes its main function is to add numbers to a running total but that's almost a side effect of how it works as a key driven machine a more fitting name borrowing from a more modern term would be a real-time calculator [Music] the Comptometer is deceptively simple in how it works you press the numbers and they're added to the visible register but in this simplicity lies its power so much so that Comptometer opens schools that taught lessons on how to use it as it gained popularity other institutions offered their own courses such as this college that had 25 students join in after hours uncredited course just because they wanted to learn more about how to use one of these which brings me to this video sponsor if there's a topic that you want to learn more about you may want to check out skill share skill share is an online learning community for creatives where millions come together to take the next step in their creative journey Skillshare courses are formatted as video lessons that are broken up into segments making it easy to spend as much or little time in your day on learning a new skill as you want the available courses cover a number of different topics like web development graphic design and video production I've been trying to get into producing music for my videos more recently and I've been working with my MT 200 using s CQ 24 as a software sequencer I started watching this series on creating music with a sequencer for this segment and I understand it because I had a lot of good general information in it even though I hadn't heard of this genre before the first 500 of my subscribers to click the link in the description will get two free months of premium so you can explore your creativity now back to the Comptometer now I want to give you a historical background of the Comptometer but I think it's important to first get an understanding of what makes the Comptometer different compared to other adding machines this machine is key driven that means the instant you release a key it starts doing work this is in contrast to devices over the time like the Burroughs portable that acted on the numbers only when you pulled the crank this is a subtle difference but it is very significant in how you use the device performing addition is lightning fast because you just have to key in the numbers you want to add they are added together in the register at the bottom without you having to do anything else the crank is instead used from when you are done and clears the register back to zeros also called ciphers at this time and even that is a quick and easy action that won't take you away from working too much now let's discuss its history I mentioned in my recent video about the Burroughs portable adding machine the mechanical revolution that was going on in the 1880s the Comptometer was the first new calculator design released during this period while the arithmometer was first out right by decades it was a very different style of machine made using much older production methods and in the last decade of the 1800s more adding machines were produced by new manufacturers than in the entire 50 year production run the arithmometer had up to that point the Comptometer was created by door I felt it was patented and produced in 1887 it was an evolution of an earlier keator of an adding machine patented by Thomas Hill in 1857 while a patent model was built for that unit it was never commercially produced the Comptometer patent model moved the display to the front and sloped the keys to make them easier to use like a typewriter felt worked with Robert Tarrant to set up a production facility and the resulting company was named felt in Tarrant manufacturing company the Comptometer was their first product two years later in 1889 they released an additional model the comp de Graaff a printing version of the Comptometer this still beat the Burroughs adding machine to market and was the first printing adding machine sold and something really cool from historical perspective this one in this picture is literally the first one sold and it is now in the care of the Smithsonian the compa graph was relatively short-lived though after being split off in 1902 as a new company compa graft stopped production at the beginning of World War 1 other than that there weren't many other major types of Comptometer made there was an option to get them equipped as a super totalizer that would allow you to add the contents of the main register to a second register and there was an electric version of the Comptometer that didn't sell particularly well as a machine didn't really benefit from that in any way Comptometer x' were more of a moving target with successive models adding enhancements and continuing features from the old ones but they stayed consistent in design eventually the company behind the Comptometer emerged in the 1960s to form some loc Comptometer but this was mostly to get the brand name has the existing models were all dropped completely and replaced with new models from their new parent company bell punch in the UK this merger resulted in the first ever elect a calculator being released as a sun lock Comptometer though was designed completely by Bell punch being a comped ometer in name only early on amongst the competition the Comptometer stood out being a key driven machine meant it didn't need to waste time being cranked results were computed as quickly as the operator could input the numbers much of the early advertisement and documentation for the comet er focused around this speed benefit the skill of the operator being so important to this speed is what prompted Comptometer to open schools for training their users there was real and long-lasting demand for those who could quickly operate a comet er I was able to find this US Department of Labor survey from 1971 that lists the salaries of Comptometer operators that's 84 years after it was introduced and during the time that electronic desktop calculators were becoming mainstream Comptometer z' could still keep up though something we'll take a look at later other companies took notice of this speed advantage and the kilometre had clones starting to pop up very early boroughs notably and shamelessly completely cloned the Comptometer down to the way the case was made this brought on a suit by Felton Tarrant which they won Burroughs was forced to change the external design of their calculator but were still able to continue producing a Comptometer competitor as more clones popped up Comptometer was put into a position of defending their trademark name to prevent it from becoming genericized because everyone ended up calling all key driven calculators Comptometer x' all right let's take a closer look at the Comptometer I have here this is a model H which would have been made sometime in the 1920s the model H carried over features from previous models duplex keys which meant it could accept multiple keys being pressed at once the controlled key for error correcting and the carry over levers both of which we'll take a closer look at in a bit and one final existing feature would be the decimal indicators on the front but these are really only useful for division and even then you could work without them the main new feature the model H brought to the table would be its clear signal ready indicators these gave you three different forms of feedback to ensure the register was fully cleared when he pulled the crank visually the zeros are off-center audibly the first key press after clearing produced a ringing by striking a bell and tactually by requiring more force on the first key press though I find this effect hard to feel in the keys towards the front in very pronounced at the back the touch and bell were the more important additions here though because Comptometer operators were actually trained to use a machine by touch only much like how you should learn to type on a keyboard without looking at it the keyboard lacks a definitive home row but the keys do alternate between flat and concave tops to give you a tactile feel of where you are additionally you'd be trained to move your hands as little as possible this was achieved by limiting yourself to just the 1 through 5 keys it's clear whoever was using my Comptometer originally was a well trained operator because the 1 through 5 rows are significantly more worn than the 6 through 9 rows are it was faster to do 2 or 3 keystrokes to add the smaller numbers up to the larger ones and then it was to move your hands and rehome now looking at the keys you may be wondering why there are two sets of digits the smaller set of numbers are called ko digits and they're how you do subtraction on the Comptometer but really any calculator those numbers represent the nines complement of the digits of the keys or for the principle is if you add the nines complement of a number you want to subtract then ignore any carryover and add one you will get the result of a subtraction so if we want to subtract 63 from 88 first we will enter 88 then you will subtract 63 by pressing the small numbers from here we could either ignore or remove the one carried over and add one to our result and we get the correct answer 25 the efficient way to do this on a comp domitor is to subtract one less than the number you want 62 in this case and use one of the carryover prevention levers to prevent the extra one from showing up to begin with I want to explain why you have to add or minus one so you can understand why you have to do it and help explain 9s complement subtraction overall forget about how we're getting the end result we want and just imagine the subtraction process as adding a negative number on the Comptometer there is no way to input a negative number so instead we want to work with a positive number if we add 99 to the two-digit number we want to subtract it is guaranteed not to be negative anymore at this point it would help to think of the numbers now being overloaded with 99 in some way that needs to be reversed later now that both the numbers are positive we can proceed as if we were adding two standard positive numbers but the result takes on the overloaded when we do an overloaded addition we get a much larger number than our intended result for a subtraction but it is visually similar the most significant digit is just off by one and we can drop that but when we try to remove that we are effectively subtracting 100 from our final number this also removes the overloaded State we did earlier but we're now under loaded by one so if we add that one back we now have the correct answer using nines complement values on the keys is just like adding a nine to a negative number so anytime you need to subtract a nine digit you can skip it when you take one out of the number you want to subtract you're getting that extra underloaded one out of the way in the beginning of the problem then you are free to ignore the added value in the most significant digit by holding the carry over prevention lever there's only one other trick to 9s complement subtraction you need to remember if you are subtracting a number with fewer digits than your starting number you need to borrow a zero with the nine keys to match the number of digits if you don't your most significant digit will be one greater than it should be borrowing a zero properly rolls over the digit counters so the result you want appears on the register note that you do not need to borrow zeros for least significant zeros and you minus one from the first digit that has a nonzero value so if you're subtracting 50 from 100 you would have to subtract with the keys zero four and nothing to get the correct value okay that's a lot of nice complement info but you don't need to remember all that when you're doing subtraction you just need to hold the carry subtract the number you want minus one with the small keys and it goes by very quickly when you're used to it speaking of very quickly let's move on to multiplication because the Comptometer is incredibly quick at that the burroughs machine had a repeat key so you could hold down the keys you wanted to multiply while you pulled the crank the Comptometer doesn't need that since you just press the keys you want immediately so if you want to do 12 times 12 you just press 12 in the first column twice move over one digit and press it again that's it you could do this as fast as you wanted but since you can change which Keys you press with every keystroke you can use another method here is 12 times 12 again that way this method works with rows that lets you keep your fingers together saving you time on placing individual fingers let's take a look at an example of this one a book on how to use the Cocteau meter you need to pay attention to three things about the number when you're multiplying it what number you are multiplying by is the row you place your fingers on the columns your fingers are on will match the number of digits in the number you are multiplying in the number of times you press each key is the same as the digits you are multiplying this is a little complicated to wrap your head around at first but as you practice it it begins to make sense and I could easily see how this method would be faster especially for those who were trained on the 1 through 5 rows since you could easily adapt this method there by combining rows now pressing multiple keys at once isn't the easiest thing especially during rapid operations like multiplication sometimes you may not press the keys down fully the register digits have gears on them and are moved by a tooth bar that meshes with the gear attached if you didn't press the key all the way down the bar may not move the gear enough and add the wrong number the Comptometer had a feature added to detect this though the controlled key when a mistake is made this key pops up the entire keyboard locks except the column that was miss pressed you can clear this locked state in one of two ways you can either repress the key in the unlock row and then press the controlled key or pull the crank and start all over again it is somewhat unsettling to have the keyboard just lock up when you're using it so I would say this feature does its job well it can be easy to correct but you don't always know what's number you were trying to type so I would just pull the crank and start again now it's finally time to cover division this is always the most complicated thing you can do on an adding machine and the Comptometer is no exception but for a different reason first off the usual pen and paper method of adding machine division works perfectly fine and is actually very quick you key in the number you want to divide on the left and subtract the number you are dividing by until you can't anymore and write down the number of keystrokes you do this just like before using 9s complement then you move on to the next digit until you've worked through the entire number but the Comptometer has another weird trick that will put the result in the register as you compute it but the manual doesn't explicitly tell you how this works I'm not sure if this was to try and prevent competition from copying it or if they just didn't want to take the time to explain it but it's a quite clever use of the nines complement rules let's start off with simple bit of division 36 divided by 12 this trick has you do subtraction but not prevent the carryover if we do normal division like this every time we subtract we get a carry this will happen as long as the number we are dividing is greater or equal to the number we are dividing by because the 9s complement numbers will make it carry one after three subtractions of 12 the number we're dividing is 0 and it was carried three times which is our answer the number to the left effectively becomes a stroke counter like you normally do in your head for the pen and paper method but it gets weirder let's do 64 divided by 8 because there are fewer digits in the number we are dividing by we need to borrow a zero and we can't subtract 8 from 6 so we will start on the 4 column after running through it it worked here as well producing 8 as the answer but the real trick to the Comptometer division is that you don't need to borrow a 0 if you do the same motions as if you were borrowing the 0 the result just ends up one column further to the right the difference is you can't see when you fully subtracted your number if you don't borrow the 0 but part of the trick is that you can always subtract at least the number of times that is shown in the digit to the left of where you are subtracting you are trying to catch up to the number of key presses in that digit which means that if that number increases you need to keep going to match it when you've caught up it is the same as having made the most significant digit 0 in the number you are dividing you repeat this process on the next keys to the right in the same way catch up the key presses and then subtract until you can't eventually this will put the correct answer in the display a larger example would be 365 divided by 7 to get the number of weeks in a year you can see I have to keep moving to the right and catching up the key presses but eventually the correct answer of around 52 point 1 4 is found and displayed this takes some focus but overall it works pretty well this method is only feasible on a device where you can watch the register change and is made much quicker by not needing to pull a crank the manual goes on after this to show how you can mix this with the row based input like multiplication but frankly that would add way too much more effort to this process and I'm just here to have some fun this method is already plenty fast and if you really want to delve in to this the book I've been referencing here will teach you how to work with fractions calculate interest and even find square roots but I think we've covered enough for now we have one last major topic I think is worth talking about now that you've seen how all the operations are performed you have an idea of how they work this device may seem antiquated today but how does it actually stack up against an electronic calculator its speed was a big selling point so let's find out how quick it was this is my Sony so box ICC 1600 that was released about the same time as that labor survey I mentioned earlier I'm going to run through addition subtraction multiplication and division simultaneously so you can see how they stack up and the Comptometer is at worst only as fast as the calculator in much faster for simpler operations this will depend on what you're doing and I did pick numbers that are easy to work with complex division will favor the electronic calculator for longer repeated operations but the Comptometer has its own advantages if you were doing simple additive accounting the Comptometer is ability to have entire numbers keyed in at once makes it faster than the processing ability of the 10 key limited calculator and I think that is finally everything I can talk about for the Comptometer being totally honest I didn't fully understand what I was getting into when I bought this thing I paid much more at an antique store that I normally would have liked but I could since there was something special to this and I have absolutely no regrets about it this is easily tied for my favorite calculator in my collection now with the so box it is amazingly capable for being so simple and it just comes down to a few clever features in learning how to use it has made me real are some bits of math and new ways that I really like I don't think I'm ever likely going to get my hands on an original arithmometer and definitely not one of the 20 Pascal lines out there so the Comptometer is realistically the earliest example of a calculating device I can get and it in no way disappoints I hope you enjoyed this look at a Comptometer hand if you to support the channel I am on patreon but for now that's it I'll see you later actually that's not it there are a few more things I couldn't fit in that are interesting the yellow digits are like that to match the colored keys the case is copper plated but coated and even lacquered on the front plate the inside is amazingly dense like it is woven out of metal the case is covered in cork to silence it and rolling over the digits is awesome

Channel: Tech Tangents

Views: 50,835

Rating: 4.9012799 out of 5

Keywords: Tech Tangents, AkBKukU, Calculator, 1920s, Comptometer, Comptograph, 100 year, old, vintage

Id: fe-9uTVMQlo

Length: 18min 47sec (1127 seconds)

Published: Tue Feb 18 2020