This is called a Rapid Computer. This particular one was made between 1906 and 1908 in Michigan. Its outer case is made of nickel-plated brass, and it has 9 vertical brass sliders at the top, which you control with a stylus. Further down is a celluloid window showing a 9-digit register, which is a row of 9 number wheels on a common axle. Each slider has the numbers 1 to 9 on them, and to add a number to the register, just put the stylus on the correct digit for a column and slide it down until the stylus hits the stop bar. When you release the slider, it springs back up to its original position, and the corresponding register wheel will have increased by your chosen digit. The register has a carry mechanism, but it can be difficult to execute a carry when several numbers have to roll over because it does not use stored energy.
There is a clearing knob on the right, on the axis of the register. To clear the register you have to pull out the knob slightly to unlock it, and then turn it anti-clockwise almost a full turn. This resets all the number wheels. You must then turn the knob clockwise back to its original position, where it will lock into place. If the knob is not returned, then the register will not correctly perform carries.
It has serial number 3198, which is stamped on the front, along with the text "THE RAPID COMPUTER CO. / PATD. 1892". Further text is hard to make out, as it has worn away and probably was stamped in very poorly in the first place, but above the serial number it used to read "Benton Harbor, Mich.". Later machines have the line "Other Patents Pending" below the serial number but this one probably did not.
It comes in a nice storage box, and with a stylus. The stylus seems to be a nut pick made by H.M. Quackenbush, inc. of Herkimer, N.Y., so does not belong to this machine. It is hard to tell how old the nut pick stylus is as Quackenbush made them for many decades, but it looks the part.
This machine is often classified as a chain adder, but it actually uses toothed racks, a bit like the Stima does. When you push a slider downward, it travels over the top of its corresponding number wheel, and the ratchet teeth underneath the slider push that wheel around. When you release the slider, it is pulled back up by a spring without moving the wheel back.
The original patent makes it clear that the width of the columns exactly matches the width used in bookkeeping ledgers, so that one could place the machine on the page and exactly line up the sliders when entering the numbers, thereby reducing mistakes.
Below is a video I made that demonstrates the Rapid Computer.
This machine was invented by Peter J. Landin from Minneapolis in the early 1890s, and he received a patent in September 1892. Apparently he set up a company, the Landin Computer Company, to produce it, though it is not clear to what extent this "Landin Computer" was actually made and sold, since almost none seem to be in existence now. He filed patents for a cash register around the same time ( US 526,400 / US 526,401 / US 526,402 ), so he may have concentrated on commercialising that. He later has patents for a phonograph ( US 1,422,453 ) and for subtitling films ( US 1,234,046 ).
Some ten years later it was marketed again, and this time a bit more successfully. The Rapid Computer Company of Minneapolis manufactured and sold it as the Rapid Computer. In 1906 the name and manufacturing rights were acquired by the Metal Sectional Furniture Company in Benton Harbor, Michigan. This company had close ties to Baker-Vawter, an office filing equipment company, for whom they made many products and parts. Around this time the design of the Rapid Computer was improved slightly by the addition of a sturdy stop bar for the stylus to bump into at the end of its downwards movement.
In 1908 the company apparently relocated to Chicago, operating from offices in the Tribune building, though the manufacturing remained at the Metal Sectional Company in Benton Harbor. Note that Baker-Vawter also had offices in the Tribune Building, and this move may well be a sign of even closer cooperation between those two companies. In 1914 the Rapid Computer Company was operating from Benton Harbor once again, but note that some of the machines produced at this time are actually stamped with the Baker-Vawter company name. The advertisements seem to dry up soon after, and the manufacturing of the Rapid Computer Company may have ended then. There are some adverts in 1917 for the machine, now sold through an agent in Louisiana, but these may have been left-over stock. I found that in 1919 Baker-Vawter had a metal plant in Benton Harbor, so I would speculate that the Metal Sectional Furniture Company merged with or was bought by Baker-Vawter, who eventually had it produce other equipment.
Here is a table showing the dates for which I found advertisements, with the addresses used in those ads. It also lists some of the serial numbers seen in pictures or text I found online in collections and auctions. From the serial numbers it seems likely that the Rapid Computer Company first started a few years before 1905.
| Time period | City/state | Address | Serial Numbers | ||
|---|---|---|---|---|---|
| July 1905 | - | April 1906 | Minneapolis, MN | 641 Andrus Building / 30 Bridge Square | 1706, 1822 |
| October 1906 | - | March 1908 | Benton Harbor, MI | 35 Lake Shore Road / 271-283 Lake Shore Road | 3150, 3198, 3328, 3729, 3807, 3938, 4047, 4328, 4362, 4566, 4568, 4828, 5000, 5015 |
| May 1908 | - | December 1912 | Chicago, Ill. | 1418-2150 Tribune Building | 5379, 5590, 5665, 5817, 6100 |
| March 1914 | - | May 1914 | Benton Harbor, MI | 117-317 Computer Building | 6150, 6173, 6303, 6403, 6465, 7607 |
In Germany in 1909, the Rapid Computer was improved upon and renamed the Comptator. When entering a number in the Comptator, the slides remain in the downwards position. This allows you to see what number you entered. Only by pressing a button on the left side of the machine are the sliders released. That release button can also be locked down so that the machine acted like the original design, which allows for some simple multiplications by entering a number several times in succession. This same functionality can be seen on for example Seidel und Naumann's SuN adder.
The Comptator came in 9 or 13-column variants. It was made by Schubert & Salzer, a company based in Chemnitz, which mostly specialised in making machines for the textile industry, e.g. spinning machines or machines for spooling thread. In about 1922 the company stopped making these calculators, and the production was taken over by Hans Sabielny in Dresden, still using the name Comptator. The exact relationship between Sabielny and Schubert & Salzer is not clear to me, though. Several websites claim that it was he who made the improvements to the Rapid Computer, and that he had Schubert & Salzer manufacture the machines for him. Note however that the 1909 patent containing the improvements is assigned to Schubert & Salzer (German patents do not list the inventor, only the assignee), and the US equivalent patent lists Woldemar Reinhold Heinitz as the inventor.
The company Schubert & Rother from Dresden had also started making a variation of the Comptator called the Surot, for which they received a patent in 1919. In 1921 production went to the company Cosmos Büromaschinen Berlin, and the calculator was then called the Addi-Cosmos. A year later production was by Bergmann Universal GmbH, with the calculator being called B.U.G.. I don't know if these are three different companies, or one company that changed its name. Production stopped in 1924, at which point Bergmann Universal produced other calculators instead.
Another Comptator clone was the Addo from Sweden, and there are probably more.
I have not found any advertisements relating to the Landin Computer in online archives, but there are quite a lot for the Rapid Computer. Note that the number in the contact address for the Rapid Computer Company could change depending on where and when the ad is published.
Below is a representative sample.
There are a few advertisements for the Comptator as well.
Here are some articles related to these machines.
| Patent | Filing date | Published date | Name | Description |
|---|---|---|---|---|
| US 482,312 | 03-02-1891 | 06-09-1892 | Peter J. Landin | Landin's Computer |
| DE 221,396 | 12-01-1909 | 28-04-1910 | Schubert & Salzer Maschinenfabrik (Woldemar Reinhold Heinitz) | Comptator input release mechanism
See also: AT 52,251 B; CH 50,980; FR 410,777; US 1,020,200 |
| DE 322,508 | 25-03-1919 | 01-07-1920 | Oskar Rother; Karl Heindel | Improved input release mechanism. (used in Surot / Addi-Cosmos / B.U.G.) |
| DE 395,399 | 29-05-1921 | 19-05-1924 | Hans Sabielny | Comptator variant |
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