Once carrying a slide rule meant instant status as a brainy geek. All of that disappeared with the electronic calculator, which was actually designed on the slide rule. You can practice using a virtual Pickett slide rule at this link.

Thus, plastic doesn’t have to be the equivalent of “cheap.” Even so, the rule served the purpose as a beginner’s, low cost rule, at $2.25 in 1962. This was by FAR the least expensive rule in the 1962 line-up, priced $3 less than the next cheapest rule. The added the “N” designation in 1925 with a slightly wider frame as well as scale labels.

Or perhaps by 1909, they’d be trapped by their own product placement, not willing to compete with their flagship slide rule, the Model 4092 Log Log rule, introduced the same year . Ultimately, as with many highly desired rules, stumbling upon one at an estate sale might be the best way acquire any of the pre-1916 K&E duplex slide rules. To add to the conjecture, the “prototype” models of the Doric & were less “plain Doric” than the others, including the use of red inverse scales and even ornamented with a red star on both the slide and the cursor. Perhaps the formula of Xylonite being used didn’t work very well with the red ink? We’ve seen many rules from a variety of makers have inks that leaked or bled into the rule. In such a case, “Doric” would be a good way to hide that these white Xylonite rules could only be manufactured with black ink.

And it’s this same reason that K&E, more than a decade later, included the Fuller in their catalog as well. Beginning in 1895 and listed as the Model 1742 for a price of $28,the “Fuller’s Spiral Slide Rule” featured a single scale on a movable cylindrical “sleeve,” spiraled around at a linear length of 42 feet long , and numbered from 100 to 1000. At this length, up to 5 significant figures in resolution would have been expected for many computations.

The inner scales on the drum are very nice, a mellow white, with no damage or lifting of the paper scales. The mahogany box is very nice with most of its original finish and just a few minor scratches. There are no owner names or initials carved into the box, base, or calculator. I went on eBay and bought a Dietzgen Polymath #1733 Decimal Trig Log Log slide rulefrom the mid-1950s for $2.50 (plus $9.50 for shipping).

Many of the single-sided Mannheim types have a stator rail screwed onto and through the rules backing. This is not a problem in general, but because the backing is thin, overtightening these screws can wear out the countersunk shoulder in which the screw rests, eventually widening and no longer holding the rail firm to the backing plate. This can be revealed often times in pictures when there’s larger gaps than you’d expect when the slide is in place. Victor Mayer Amédée Mannheim (1831–1906) brought up the modern version of the slide rule, around 1850, with a new scale using a runner. The basic process for setting up and solving problems is the same for operations on other scales.

Keuffel & Esser 1744 Duplex Slide Rule

Dietzgen was heavily influenced by his father, one of Karl Marx’s favorite philosophers. He provided his factory workers with many amenities not often found in the 19th century. These included separate bathrooms for men and women, open windowsills with flowers decorating the air, and a general atmosphere hookupranking of a healthy working community. Dietzgen ‘s first wife could not bear him children; they divorced, and in 1912 Eugene moved to Zurich, Switzerland. There he met his second wife, Jansen, and they had three boys and three girls. A nice piece that will display well and be a great addition to the collection!!

Connect to History

For example, while the Model 4097C of the Ever-There is important to that “series” of rules, it functionally works as the fulfillment of a pocket rule for the Merchant’s “family” of slide rules, and as such, will be highlighted in those conversations as well. This mahogany wood 10” slide rule with scales on the front and back was more expensive than the plastic, one-sided models. This slide rule belonged to Dr. Harry Blum, a mathematician who worked at the NIH Laboratory of Statistical and Mathematical Methodology in the Division of Computer Research and Technology from 1967 to 1982. The inner scales on the drum are very nice as well with no damage or lifting of the paper scales. Note from the end shot the condition of the felt pads on the insides of the drum. The mahogany box is very nice and has most of its original finish.

It is, after all, a major selling point for duplex rules. Osvaldo, someone called slide rules “the original pocket calculator.” And, you never need to worry about needing new batteries or having enough sunlight for the solar cell to provide enough power! Apparently some people still prefer them to electronic calculators and use them for real mathematical calculations.

Keuffel & Esser 4088-3 Polyphase Duplex Slide Rule

Instead, it’s the former point – that the smaller form factor was suitable for this rule – that makes sense when you compare the front of the Cooke rule with the Model , which despite its smaller rule height has some tradeable assets. It is unlike earlier two-line cursors used around the turn of the 19th century when the scales were a 0.5 cm from the end of the rule. In this case, if the diameter of a circle is set on the right hair-line, then its area can be read from the left hair-line. The center hairline is used for all other computations normal to the rule. Second, there is a centimeter ruler on the back of the bottom stator of the rule, and it is divided atop a celluloid lamination.

The speed with which these developments unfolded suggests the power that logarithms provided for reducing the tedium of calculation. By the 1680s, the English used slide rules in carpentry and in gauging —the instruments were quite helpful for determining excise taxes on barrels of liquor. The serial # is 1678 and this can be found on the mahogany mounting board near the top along with the eagle logo and K & E name.

As we talk about the modern K&E rules and their evolution to all-plastic construction, it should be expressed that the actual composition of plastic being used is never explicitly revealed. As plastic became more widely used, their composition and methods would have been a finely guarded secret. So as collectors of slide rules trying to understand their evolution, it can be confusing for us. The LL00 extends the LL0 scale, splitting exponential bases between 0 and 1 into two scales to give another significant figure worth of precision. In this implementation, the LL0 is extremely accurate now, covering only bases from .999 down to .905, while LL00 scale handles .905 to 0.

Celluloid is a bioplastic, produced from a cellulose substance , nitrated , and then mixed with a plasticizer . It wasn’t until 1907 when Bakelite, the first all-synthetic plastic, was formed. And thus was born the concept of the Trig and Deci-Trig versions of these rules. Bruning produced their own rules, but a greater number of them existed as rules licensed to other companies.