www.AntiqBuyer.com antique slide rule / calculator past sales

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c. 1700 Pierre Fardoil Adding Machine & Watch / Time Piece I am half owner of this rare and early Pierre Fardoil Adder / Adding Machine and Fardoil Watch / Time piece, and in an attempt to finalize the sale of this Fardoil adder with my partner I am going to offer a full or partial interest in my 1/2 ownership in this rare 18th c. Fardoil adder for a nominal sum to the right person or entity who can facilitate a sale with my partner.

Here is the history of this piece---please read on.

The Fardoil adder is one of the earliest and rarest 18th century calculation devices known. The 2 pieces pictured are the very same Fardoil Adder / Adding Machine and Fardoil Pocket Watch that reached a sale price of approx. $70,000 at the Auction-Team Breker sale about 10 years ago. Here is a web address to that auction result and the original write-up that can be found online: www.liveauctioneers.com/item/36708195_the-adding-machine-of-pierre-fardoil-c-1700. The same two pieces are currently listed for sale on my partner's website for $70,000 or so.

This Fardoil adder is one of only two known, and this could be the only known example if it is the very same Fardoil adder that the French Musee des Arts et Metiers (CNAM), the French State Museum, and their representatives claimed was "lost", stolen, or otherwise disappeared from their collection when it was on display in the US during 1939 New York World's Fair.

At the Breker auction some 10 years ago the high bidder for this Fardoil Adder was Professor Korte from the University of Bonn, who was bidding to acquire it for the Arithmeum museum in Bonn, Germany. The high bidder backed out from finalizing the Breker auction sale due in part to the CNAM claim. The underbidder also backed away when it was subsequently offered to him.

The two Fardoil pieces were then returned to the consignors---myself and the other 1/2 owner, who is Peter Frei, an antique dealer based in Massachusetts. He is my ex-friend and current partner in the two pieces. He is currently in possession of both pieces.

Peter Frei and I had been partners in numerous endeavors involving technology-related antiques prior to having a falling out. Our friendship ended one day when Peter, in a fit of rage, over a situation concerning an antique sewing machine which I had paid for that we were 50 / 50 partners on, entered into an agreement with a 3rd party, offering him 50% to sell it---thus making me a 25% junior partner. Peter did that without consulting or discussing that decision with me. When I questioned his decision he got insulted and declared we were no longer friends and said our partnership was over. This was after we had already purchased the Fardoil Adder. There is more to this story that is irrelevant to this sale that does not need to be retold here.

But what should be told is the story of who first found the Fardoil adder---that would be me---and details surrounding that event, and the Breker auction. The Fardoil sellers, who lived in NY, contacted me and I made an appointment to go see it. They told me that the adder had been "found" in New York, and their now deceased family member had been a caretaker / custodian / groundskeeper / employee and "found" it where he worked. The family told me they had had it appraised at Sotheby's or Christies auction house for 5K, and I offered to purchase it from them the same amount in cash.

The family initially said no, but months later called me and said they were ready to sell the Fardoil. As I was back in CA by that time I called and enlisted Peter to go and get it. I offered him to be 50/50 partners on the Fardoil. He agreed and went and got it. We split the cost 50/50. He later bought the Fardoil watch and we split the cost of that as well.

For various reasons Peter handled consigning the Fardoil to Breker's Auction. The Breker auction failed after the French Musee des Arts et Metiers / CNAM cast doubt on the rightful ownership of the Fardoil and the Arithmeum backed out of the sale. After the auction failed to produce a sale we agreed to let Peter market the Fardoil to the under bidder or other parties. It was offered to the under bidder, but that too failed to produce a sale over the price. Later the CNAM made a relatively low offer, not to purchase it, but rather as compensation for us having found it and returning it. That offer was rejected. Peter made several other attempts to sell it but failed to find a buyer.

Then something akin to the storyline in Lord of the Rings began to unfold, and the "my precious" concept began to take hold, much like with Gollum and his precious ring in the Lord of the Rings story. Peter, despite saying he was ready to sell, and that he wanted to sell it, and acknowledging that I am his 50 /50 partner on it, could not bear to let the Fardoil go, and has refused to let it leave his hands.

The disclosure of these details is necessary because provenance / history of ownership of important historical pieces is vital to establishing and enhancing an objects value. In addition I want to insure there are no claims of non-disclosure or other problems down the road from the buyer of my 1/2 or partial interest.

The attempts for Peter and I to settle up on the Fardoil after the failed auction should also be told, again so that potential parties interested in buying into my 1/2 share are fully informed and can better formulate a plan to finalize the sale.

Over the next 10 years Peter offered several proposals to resolve the Fardoil situation between us---all in writing and documented---but then reneged on following through on every single one of them. For the record, let's review some of those past proposals:

Immediately after the auction Peter wrote that if the high bidder or under bidder would not pay the original sale price it had brought at auction he would simply buy us out for 1/2 of the high bid, as we both felt it had not reached its full potential because of the French interference. He never followed through on that proposal, later claiming it was just a negotiation tactic. Problem is he was not negotiating with anyone at the time.

Shortly after Peter ended our relationship he announced we would settle up over the Fardoil by having a private auction between us, with a third party holding the Fardoil until that process was complete. He reneged on that proposal soon after, claiming he did not have enough money.

Peter next demanded we wait and be patient, as the Fardoil was, in his words, "burned" by the French claims, and the failed auction.

In 2019, 5 years after the auction and after numerous requests, by us, to resolve the situation, Peter said to wait one more year to see if he could sell it from his new website. In writing he said that if it did not sell from his website at the end of the 1 year period we would send it to auction again. He proposed that, in writing, and then reneged on that solution with no explanation or excuse.

Peter next suggested we should name a price he could buy us out at, with the stipulation that he would need 6 months to gather the money. A proposal that was neither fair nor equitable, but in the interest of ending this ordeal we proposed selling our half interest to him for $18K---approx. 25% of the original sale price of $70K it had reached at the Breker auction, approx. half of what we would have been due had the auction succeeded---a reasonable offer by us to resolve this.

Peter rejected that offer outright saying he would never pay that amount, with no meaningful counter or discussion. That was over 2 years ago, much longer than the 6 months he said would be needed to raise funds to buy us out, once again reneging on a proposal he himself put forward.

Most recently in Dec of 2024 we suggested listing it for sale on our two websites, at a lower price, to give it more exposure and to further enhance its desirability and value. To do that we needed to discuss a price beforehand that we could both agree to. Peter declined, and instead wrote he alone would decide if he would agree to a lower price AFTER I found a buyer---a stupid and unworkable proposal not worth discussing further, and mentioned here only to illustrate the absurdity.

After all of that we have decided to take on a partner or sell our 1/2 interest in the Fardoil. Our hope is that a qualified and interested 3rd party with a new or different approach might be better able to deal with, or negotiate with, Peter better than I.

I am going to try to make this simple, reasonable, and enticing with a lot of potential upside for the right interested party. Here is my proposal. One option would be to purchase my 1/2 share ownership in it's entirety for some agreed to amount. That can be outright, or over time with the details to be worked out. Since that is probably over-optimistic given the situation, I do have a alternative idea to present.

The second option would be to purchase a portion of my 1/2 share for a small upfront investment. In other words with a reasonable buy-in I will agree to split the proceeds of the final sale of the Fardiol with my new partner for a very small initial investment. This would require a qualified and acceptable individual, or entity, with a plan or concept of a plan, and the ability, to force a sale of the Fardoil.

I am thinking the initial investment would be something on the order of $100 in return for the right to a minimum of 25% of the total sale price---50% of my share of any final sale. The potential return could be enormous. A reasonable expectation could be, using the Breker auction result of 70K, a payout amount somewhere in the $18K range for each of us.

If the Breker sale price had in fact been held down because of the French interference, the payout could be far more if the Fardoil was again sent to auction and brings more than the $70K it brought the first time it sold. Or some uber-wealthy party might pay even more in a private sale.

Or you may be able to get Peter to agree to sell his half-interest to you and gain full ownership.

Another possibility is the French may step up with a larger offer than they first offered. Or the French could enter into this partnership and make a claim of complete ownership in court. The French could end up being declared the sole owner at little further cost.

The possibilities are many, but in any event you are going to have to have the ability to make it happen in order to pry it out of Peter's hands. We can make a gentleman's agreement to reflect this, or I will sign an acceptable agreement drawn up by the new partner or their representative. I am very flexible and very willing to work with the right person or entity to resolve this and to get the Fardoil into more appropriate hands.

This proposal to form a partnership for an interest in our half interest of the Fardoil would be a great deal for the right person or entity who thinks they can negotiate with Peter Frei, or otherwise close the deal, or force a sale. Just think, a documented ownership in a rare, probably one-of-a-kind and unique piece of calculation history for a fraction of its potential value!

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FARDOIL

Price . . . . . . $ TBD

To Order Email: patentedantiques@gmail.com

Pickett N4-ES 4' Classroom Teaching Aid Slide Rule The condition of this 4' teaching aid sliderule is exceptional. It is model # N4-ES Vector Type Log Log rule a more complex model than the more typical classroom size N-1010 you see offered all the time. It has 34 scales. It dates from around the 1960's and just before handheld electronic calculators hit the market big time. Nice!!

Fine . . . . . $350.00 SOLD!!

Pickett N1010-ES Trig 4' Classroom Teaching Aid Slide Rule The condition of this 4' teaching aid sliderule is very nice. It is model # N01010-ES Trig rule. It dates from the 1960's or 70's. I do not think it was ever used. Nice!!

Fine . . . . . $325.00 SOLD!!

Fine . . . . . $375.00 SOLD!!

Hutton's Commercial Slide Rule by Nestler

Hutten's Commercial Slide Rule by Nestler The overall condition of this unusual merchants sliderule is nice. There is a small stain on one end. There is no damage to the rule, cursor, or hard black case.

Fine . . . . . $45.00 SOLD!!

Sun Hemmi # 256 Electronics Slide Rule This is a nice condition rule still in its marked plastic sleeve. It has seen little use. It has a very unusual setup on the back side and is geared toward electrical calculations.

Good + . . . . . $75.00 SOLD!!

A. W. Faber "Castell" No 378 Electronic Slide Rule This Bavarian made slide rule is geared toward electrical calculations with the words Dynamo, KW, HP, Volt etc. There are numerous sites online that discuss its use. It has 3 cursor lines. It is in fine condition as is the case.

Fine . . . . . $34.50 SOLD!!

A. W. Faber Slide Rule w/ Hard Case & Decimal Keeper Cursor The condition of this Sliderule w/ unusual cursor is very nice. There is no damage to the rule, cursor, or hard black case.

Fine . . . . . $50.00 SOLD!!

US Blue Co. 1876 Sun Hemmi Slide Rule w/ Magnifier This bamboo and laminated plastic sliderule is about 11" long. The case says it is an 1876, and that is US Blue Co's number. This rule has its own Sun Hemmi number that I could not figure out and the rule itself has no model #. The interesting and rare feature here is the flip up or extendable magnifier. I found other examples w/ rectangular magnifiers, but no other round ones like this. I believe it dates from the 20's - 30's. Nice!!

Good + . . . . . $75.00 SOLD!!

Sun Hemmi 259D Engineering Slide Rule Pretty nice.

Fine. . . . . . $45.00 SOLD!

Faber Castell No 2/83N Novo Duplex Slide Rule This German made slide rule comes in its plastic case with instructions in German. It is in very good condition. It has some minor areas of discoloration / browning along some edges. It has 3 cursor lines. All the scales and other printing are clear and bold. The cursor is nice. There is a small break in the plastic case lid (top left corner) as shown in the pics. There are numerous sites online that discuss it.

Good + . . . . . $175.00 SOLD!!

Post 1460 Versalog Slide Rule An early version edge marked on the rail with model and maker info. Like new in the box. Nice!!

Fine . . . . . $75.00 SOLD!!

Charvoz Aristo 971 Hyperbolog Slide Rule This German plastic sliderule is like new in the box w/ case and instructions. Nice!!

Fine . . . . . $75.00 SOLD!!

Faber Castell Slide Rule 2/83 w/ Case and German Manual Overall nice condition. All plastic, good cursor. Includes plastic case and manual in German. One of the last rules Faber Castell put out.

Good + . . . . . . . $125.00 SOLD!!

Pickett #52T Air Force Photography Slide Rule This aluminum sliderule is a Type 1-A. It is in like new condition.

Good + . . . . . $50.00 SOLD!!

Sun Hemmi #269 Civil Slide Rule This sliderule is like new in the box w/ hard case. Nice!!

Fine . . . . . $65.00 SOLD!!

Pickett #520-T Air Force Photography Slide Rule This aluminum sliderule is a Type 1-A. It is in like new condition still in the wrapper. Nice!!

Fine . . . . . $60.00 SOLD!!

Post Versalog 1460 Slide Rule Made by Sun Hemmi. This is a very nice bamboo rule.

Good + . . . . . $50.00 SOLD!!

Post Teledyne Versalog 44DA-610 Slide Rule Made by Sun Hemmi. This 6" Versalog rule is the same as a 1461. A very nice bamboo rule.

Good + . . . . . $95.00 SOLD!

Calculator / Slide Rule Pen These mechanical pencils are a pretty neat calculator / slide rule designed to do multiplication and division. The instructions are here, but pretty tattered.

Good+ . . . . .$150.00 SOLD!

A. W. Faber #367 Slide Rule w/ Keeper Cursor This unusual slide rule is in very nice condition and is w/ its original hard case w/ advertising. Slide Rules with unusual style cursors like this are very hard to find. This cursor acts has what is known as a Keeper or counter allowing the user to keep track of his calculations as he works on a problem. The condition is super with just minor l9osses to the label on the box.

Fine . . . . .$145.00 SOLD!!

Fowler Long Scale Slide Rule / Calculator Fowler is a well known English name in circular sliderules / calculators. They made a variety of different models and size calculators including many circular versions like this one. Some were designed for architects, or engineers, and others were made for the textile trades. Larger ones are referred to as Magnums, and this 2 3/4" model is referred to as the pocket size. This Long Scale Fowler calculator is in super like new condition with its outer hard shell marked case. The original instructions are included as well. There is a plaque inside the case that gives the location as Manchester England. There is a serial number under the glass on one side, but there is no specific model designation other than the long scale that I can see.

Excellent . . . . .$495.00 SOLD!!

Ross Meridiograph This is a field used calculator to determine the true azimuth. I suppose for use prior to setting up a solar transit or compass in areas where their use was required. It is by Ross who also made another unusual slide rule. There is a lot of paper that goes with it so be sure to see all the pics.

Fine . . . . . .$75.00 SOLD!!

Pickett N 300 T Slide Rule in Case w/ Box This is like new. A nice 6" rule!!

Fine . . . . .65.00 SOLD!!

Farm / Gestation Circular Calculator / Computer / Slide Rule

Vernon Farm Calculator / Circular Computer / Slide Rule for Farm / Gestation This unusual 12" farm related advertising circular sliderule / calculator dates from the 40's -50's. It was made by the Vernon Company of Vernon Iowa and was copyrighted in 1948 by George De Vries. They can be found with many different names and locations from all over the Midwest. I believe they were give-aways from different seed companies, grain dealers and farm equipment dealers. This one is from an outfit, Glen R. Green of Ridgeway MI that dealt in Ferguson Tractors and farm equipment.

They were a very well made device that held up well over the years and many are found in super condition. That is probably explained by the fact this was a solution looking for a problem that did not really exist. I doubt many farmers of the time really saw, felt, or understood the need to use it and most ended up in the drawer or hung on the wall. Look at all of the pics to get a sense of all the different things this could compute for the user. An interesting calculator in super condition.

Fine . . . . .$65.00 SOLD!

Circular Calculator / Computer / Slide Rule for Farm / Gestation

Vernon Farm Calculator / Circular Computer / Slide Rule for Farm / Gestation This unusual 12" farm related advertising circular sliderule / calculator dates from the 40's -50's. The condition is like new. It was made by the Vernon Company of Vernon Iowa and was copyrighted in 1948 by George De Vries. It is complete with instructions for use. These calculators / computers can be found with many different names and locations from all over the Midwest. I believe they were give-aways from different seed companies, grain dealers and farm equipment dealers. This one is from the Critic Quality Feeds a well known outfit from that period.

They were a very well made device that held up well over the years and many are found in super condition. That is probably explained by the fact this was a solution looking for a problem that did not really exist. I doubt many farmers of the time really saw, felt, or understood the need to use it and most ended up in the drawer or hung on the wall. Look at all of the pics to get a sense of all the different things this could compute for the user. An interesting calculator in super condition.

Fine . . . . . $50.00 SOLD!!

Pickett #109 ES Circular Slide Rule This 109 ES Pickett circular slide rule is pretty hard to find, and it has its leather case as well. Nice.

Good + . . . . .$85.00 SOLD!!

Dietzgen Microglide Trig Type Log Log Slide Rule This looks like it was made by Hemmi. Nice!!

Fine . . . . $85.00 SOLD!

Post 1491 Chemist Slide Rule This is a Hemmi product. It is a pretty rare rule. Nice!!

Fine . . . . .$125.00 SOLD!

The Standard Calcumeter This is an interesting dial type adder / calculator. These can be found with different numbers of dials. This is an upgraded model with a reset dial on the far right. The patent info is on the side, and the ends are marked with a location and the serial number.

Just what every money changer needed to add up the days take or to calculate out his bonus. Very Nice!!

Excellent . . . . .$125.00 SOLD!

The Comptator Adder / Adding Machine in Wooden Case The Comptator is a multi-column adding machine with a stepped sliding mechanism. This version is marked Hans Sabielny Dresden and dates from the 1920s. This 9 column adder / adding machine is in fine condition.

To operate the stylus is inserted in the toothed slides and is drawn down advancing the register by the number of places. The slides remain in their final position so the value entered can be read back. The slides spring back to their home position when released by the lever on the left-hand side. The lever can be latched down to give an immediate return if checking is not required. The register has an automatic carry mechanism. To clear the result, the knob on the right is pulled out and turned anti-clockwise.

The machine was designed in 1891 by Peter J Landin and was patented. The US Patent # is 482312. The device was manufactured and sold as the "Rapid Computer Adding Machine" from 1893.

The Comptator name was used for an improved version built by Schubert & Salzer of Chemnitz Germany from 1909. Production was transferred to Hans Sabielny of Dresden from 1922. Sabielny was later involved in the manufacture of Facit calculators in Dusseldorf during the 1950s and 60s.

Fine . . . . . . $100.00 SOLD!!

A. Lietz Merchants / Bankers Slide Rule This rule dates from before the WWII. It looks to have never been used. The case is fine. The catalog / manual is nice, and this rule and its scales are described inside.

Good+ . . . . .$75.00 SOLD!!

Castell 63/22 Addiator Slide Rule This 6" sliderule is set up with a slide rule on one side, and an addiator, or adding machine on the other. It even has the pointer for the adding machine. Complete w/ cloth like case. It is a very hard to find combination rule / adder. Nice!!

Fine . . . . .$95.00 SOLD!!

Easterly Rafter Calculating Slide Rule This unusual rule to help the carpenter figure his roof cuts hails from Healdsburg CA. It was copyrighted in the 1940's. Different & Nice!!

Fine . . . . .$55.00 SOLD!!

Sun Hemmi #153 Slide Rule This is a nice rule in like new condition!!

Fine . . . . .$75.00 SOLD!!

Consul the Educated Monkey Calculator This is a real, early, and original model of this great idea. It is not one of the new fake knock-offs. These came out about the time of the Scopes trial back near the turn of the century in TN in the seminal case pitting creationists against teaching evolution in our schools. I wouldn't doubt that this idea was introduced as a tongue in cheek way to drive the creationists crazy. Think of it, a monkey teaching kids how to add, subtract, or multiply. Blasphemy. Maybe not though, if todays wingnuts get one more appointment to the Supreme Court who knows what tomorrows kids are going to be taught in schools. Who you voting for?
Nice!!

Fine . . . . .$125.00 SOLD!

J. Long London Proof Slide Rule An interesting slide rule for calculations having to do with determining the alcohol content, or proof, of liquids like wine of hard liquors or spirits. Such rules are oftentimes found in Sykes Hydrometer sets. The maker name J. Long, and location, 20 Little Tower Street London are on the top rail. It is in very nice condition.

Fine. . . . .120.00 SOLD!!

Sun Hemi Electrical Engineering 256 Slide Rule This is a nice looking sliderule!!

Fine . . . . .$95.00 SOLD!!

Sans Streiffe #311 Duplex Slide Rule This is a nice looking sliderule in its case w/ original box & instructions!!

Fine . . . . .$65.00 SOLD!

September 2, 1851 Patent Samuel Young Interest Calculator The patent holder of this unusual slide rule like interest calculator was named Samuel Young and he hailed from Eaton Ohio. The patent number is 8329 and the patent can be looked up using Google. It is a rare and early piece that there is little reference to or information about on the internet. The Smithsonian has the patent model for it, and has a pretty extensive write-up on the patentee. That page can be seen here http://collections.si.edu/search/results.htm?q=record_ID%3Anmah_690825&repo=DPLA

In reading his Bio there it seems he had two other patents for other calculation devices with this one being the middle one. The overall condition is pretty nice noting that one of the slides is damaged. The patent lays out how it is operated and what the scales are for and how to use it. From my reading it seems different bars represent days, weeks, months and so forth. Different and an opportunity not to be missed.

Good . . . . . $ SOLD!

Geotec 341 3012 Versalog Slide Rule This rule is mint and still sealed in the plastic. Geotec was a Canadian outfit and their rules were made by Sun Hemmi. Nice!!

Fine . . . . .$95.00 SOLD!!

Loga Modell 6400 Topo Circular Slide Rule This is a nice looking sliderule with its leather pouch.

Good + . . . . .$145.00 SOLD!

Pickett N4 Aluminum Slide Rule This is a very nice rule in its original box with case and instructions. It displays no signs of use. Very unusual and very nice!!

Fine . . . . .$75.00 SOLD!!

20" Dietzgen #1762-P Mannheim Slide Rule This is a nice looking sliderule in its original case. The rule has a bit of a sway to it, but it still slides easily.

Good + . . . . .$75.00 SOLD!!

Halden Calculex Circular Slide Rule / Calculator The condition is excellent and it is complete with its instruction booklet and flip top aluminum case. It is English and this one is only marked with the original makers name. This type calculator was offered by several different distributers like Dietzgen, and K & E and others back around the turn of the century. A piece of calculation history.

Fine . . . . .$150.00 SOLD!!

Odelco / Sun Hemmi 269 Slide Rule NOS. A Japanese Sun Hemmi product marked Odelco for the Philippine distributer. A hard to find and nice rule!!

Fine . . . . . $75.00 SOLD!!

Dietzgen Slide Rule w/ Magnifier & Humped Case

Dietzgen 3193 Slide Rule w/ Magnifier & Humped Case This is an unusual variant with a fitted magnifier and its original nice condition humped leather case to allow for that. The overall condition of the rule itself is nice. I believe it is the equivalent of a K & E 4053-3. It is marked w/ 2 patent dates. August 9 1904, and June 28 1898. Nice!!

Good + . . . . . $50.00 SOLD!!

Castell Addiator w/ Slide Rule Adding machine w/ stylus on one side, and a slide rule attached to the other side. Nice noting small chip on bottom right of rule. I see no number on the rule, but believe it is a Faber-Castell 67/54 RB Darmstadt/Addiator.

Good + . . . . . $50.00 SOLD!!

The Equationor or Universal Calculator Patented & Copyrighted by Walter Hart The Equationor circular slide rule / calculator patented & copyrighted by Walter Hart is one of the rarest and most unusual slide rules ever produced. There are no other examples, other than this one, to be found or viewed with internet searches. There is one article by Conrad Schure about the Hart Equationor in a 1992 issue of Oughtred Society's publication. Also the Library of Congress has a copy of the 32 page instruction booklet that anyone can download for free as a PDF. Beyond that there are just resellers trying to market copies of the instructions that can be had for free further down the page.

The face of the calculator has a wealth of information printed on it. In the left top corner are the 2 copyright dates from 1888, and 1889. In the left corner are patents from July 31 1888, and April 29 1890. The 1888 patent # is 387,070 and is titled Sliding Logarithmic Scale. It is viewable with a Google search. The second patent from April 29th 1890 closely resembles the calculator as it exists, right down to the sliding magnifier. That patent # is 426,444 and is titled Sliding Calculating Scale. It too comes up with a Google search.

The simple and ingenious logo Walter Hart came up with to market his calculating slide rule, that took 32 pages to explain how to use, was "Arithmetic Without Figuring". Simple Genius.

The condition of this Hart Equationor is exceptional. Many circular slide rules have a problem with the scales peeling, chipping, or otherwise deteriorating. Not so here. There is a fine alligatoring texture to the surface that looks to be factory and not damage. The face is near flawless w/ one small dent chip. The magnifier is very nice. The box is original and w/o lid. A super nice and rare piece of calculation history that will display well and be a great addition to the old office, slide rule, or calculation related collection!! Enjoy.

Fine . . . . . $6295.00 SOLD!!

Pilot Balloon Slide Rule MK IV A Pilot Balloon slide rules were made for the British Meteorological Office by different makers.

The Pilot Balloon slide rule is used to convert the observed azimuth and elevation readings into wind velocity and direction records. The use of slide rules and plotting boards was rendered obsolete with the wide spread adoption of computers and programs to do the calculations, as well as the decline in the use of optical pilot balloon theodolites.

A nice piece of calculation history that will display well and be a great addition to the old office or calculation related collection!!

Good . . . . . $225.00 SOLD!!

Alpina Adder / Calculator Here is an rare Alpina Adder / Calculator in its hard hinged case pictured. The Alpina Calculator is a hard to find calculator / adding machine, especially in this nice condition. It is in very nice original condition and the finishes are near perfect noting one small rub on the backside. There is also an empty screw hole on one end. It does not affect the function, more like to help hold the outer housing in place

These small German made calculating machines were only produced for a couple years in the 1960s and less than 4K were made / sold. I looked pretty carefully, and do not see any serial number.

It seems, and for good reason, the Curta calculator was far more popular, not to mention easier to operate, and the Alpina just could not compete. A great addition to the calculation / scientific collection.

Good + . . . . . $1295.00 SOLD!!

Dempster Rota Rule Slide Rule Model AA w/ Magnifier, Case, Manual & Box A rare and hard to find circular rule especially in this nice condition. The serial # is 1293 and it dates from the 1930s. I see no issues other than the outer box having some scuffs. A great addition to the collection.

Good + . . . . . $695.00 SOLD!!

Eastman Kodak X-Ray Exposure Slide Rule There is a copyright date of 1919 on the back side of this unusual double slide slide rule. There are also directions for use here that are pretty vague and lead one to wonder how many people they were overdosing when they were performing this new technology on patients way back when. One of the two slides that move has scales on both sides talking about the spark gap and tube distance. THe other is for the type of film used. The fixed scale on one side is all about different body parts and on the other is exposure time in seconds ranging from 1/16th to 64.

There is a slight bend in the body of this (probably due to overexposure), but everything still moves and slides as it should. It measures 2.5 x 5". The outer case as seen in the picture is a bit ratty, but the rule itself is pretty nice, noting one minor tight crack in the bottom right corner in the greenish cover. A rare an unusual piece of medical or X-Ray related memorabilia.

Good . . . . .$195.00 SOLD

Pickett Model # 6-T Statistical Quality Control Slide Rule Overall this rule is in very good condition. Special use slide rules from any company are much more difficult to find, and this one aimed at statistical analysis is no exception. I count 28 scales to keep you occupied, and I wish I could tell you the significance of them, or why this is special for statisticians but I cannot. I do know that only a few have been offered at the internet auction, and that new in the box I have seen them for a lot more money than this one.

Good . . . . . SOLD

The Smallwood Calculator The adding machine itself is near mint, as is the walnut base it is set into. Marcia Palmer did lightly put her name in the top rail. The small wooden original stylus is present. The protective case, which is a triangular cardboard box, has one end popped loose, and the patent date is on the front of it in small gold lettering and looks to be Feb. 23, 1---, with the last numbers being unreadable. These interesting and desirable adders were produced by different manufacturers over the years. This example, The Smallwood, from Oakland, CA, is one of the harder ones to find, and even more so in this condition.

Good . . . . . SOLD

Castell / Faber #2/83 Novo Duplex Slide Rule This rule is 15" long and is one of the most sought after and popular of all rules put out by this company. There are at least 30 scales, and a host of color schemes to help you keep things figured out. If you need help with them the super condition 30 page manual is here as well. There is also a conversion chart and ruler in the bottom of the case. The rule is in excellent condition, and has no problems with any aspect of it. The case is cracked across the bottom. A rare rule, and a welcome addition to the hoard.

Good . . . . . SOLD

Otis King Model A #6992 Circular Telescoping Slide Rule / Calculator Here is an early version of this English favorite, and it is in super condition. There are two scales #423 & 414, which are both in great condition, with no peeling or other problems. These earlier models were done in white on black for the scales to give them more contrast. I have had later models that were done reverse of this. This one also has a small ring at the top which later versions do not have as well. Lastly there is the calfskin slip cover that has the name still visible, but it is in a very fragile state, and both the top and bottom are missing.

Good . . . . . SOLD

This is just a sample of the many antiques & collectibles we have sold.
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We Buy Quality Office & Scientific Related Antiques
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Antique & Vintage Slide Rules & Calculators

Antique & Vintage
Slide Rules & Calculators