If you noted that the non-inverted, folded 2pi scale is not the inverted and folded 2pi “F” scale that I described earlier, then hopefully you also noticed the DI on the bottom stator of the back of the rule? If the “F” scale on the “Radio Special” was read from the D scale, then here on the Cooke the 2pi scale would work with the DI scale. So in practice, the user simply has to flip the rule over to read between 2pi and DI. This allows similar use to compute the reactance formulas discussed earlier. Morrison’s design continues to the back side whereas, according to manual, the numbered scales allow for the computing factors involving radio wave propagation as shown at right. The first question that arises is the origin of the name, “Roylance.” Many places on the Internet declare the name to be “Roy Lance,” but it should be noted that all catalog entries and instruction manuals, give the name as Roylance.
Otis King’s Pocket Calculator, Scale No. 423, c. 1922Keuffel & Esser Thacher’s (Cylindrical) Calculating Instrument, c. 1927
This was very much a special purpose slide rule and from that standpoint could be talked about among the Specialty Rules, but staying true to ISRM’s K&E Model Map, we will discuss it here with the other duplex rules. The catalog description for this rule states that “Ivorite” construction is used. We see this description also in an edited version of preface that we saw in the previous 1952 catalog . “Ivorite” is copyrighted here, which might simply mean that K&E, while their rules were already transitioned to Ivorite with the Doric rules, could now be safely called what they wanted all along. The edge of everything else showed the mahogany construction of the rule.
Introduction: Refurbish an Old Slide Rule
He saw this rule as one that non-engineers might actually buy, and any opportunity to cut into the sales of the Deci-Trig was favorable to him. This could have been a concern of K&E’s at which point the company could have taken a “better be safe than sorry” approach. This notion would support the incorporation of the edge inlay in 1952 as perhaps they did not feel it was necessary any longer?
This is a nice early Thatcher’s / Keuffel & Esser #4012 calculator / slide rule. If laid out in a line The inventors name is really Thacher, but it was mis-spelled on almost all versions of this calculator that K & E offered, hence the use of two different spellings here. There is another noteworthy feature of the rule that you might have seen and that’s the addition of F and P scales on the top stator. An F scale has been used before, denoting “frequency” in K&E’s 4082 “Radio Special” rule , and you no doubt notice that P scales (“Pythagorean”) can be found on many European slide rules. Instead, these are log log scales, whereas P is for computing positive bases of exponentials and F is for negative bases. Doing so replaces the eight scales of a typical Log Log design.
The Thatcher calculator is one of the best known and most sought after of all calculating devices that was ever produced or offered. First patented in the US in 1881, production and manufacture was originally carried out in England but was moved to the US shortly after K & E bought out the rights to manufacture the rule. There were two basic models available the 4012 and the 4013 which was basically the same rule with the addition of a magnifier which ran on a bar in front of the scales. The overall condition of this unusual slide rule is exceptional. There is virtually no spotting or yellowing except at the very end as one would expect and is the norm.
If cracks in the rails are not obvious in the pictures, then note any rust stains either at the cursor or along the slide rule rail itself. There are a number of sources of manuals for slide rules, they were usually supplied with slide rules when purchased although over the years they have become detached from the slide rule and are now lost.A number of these manuals are available for download. Peter Mark Roget (1779–1869) studied medicine at Edinburgh University. In 1814, he invented a slide rule to calculate the roots and powers of numbers. It became the basis of slide rules that were common currency in schools and universities until the age of the calculator.
Darling, Brown & Sharpe Astronomical Linear Slide Rule
Next to the original Mannheim family of slide rules, the earliest offered by K&E are rules from their Stadia Family. Recall that early demand for K&E products was from an industry that was actively building and expanding the country, which meant that land surveying was big business. A method known as the “stadia method” for surveying was the most advanced method used up until the technological age of laser range-finders and GPS, requiring optical tools for which K&E, of course, would provide. With these tools, a survey crew could measure the height and distance of any object given any “line of sight” to which the optical system is capable. The stadia method is still in use today, as the method is simple and accurate enough for a variety of range-finding and topographical applications, without having to spend thousands of dollars on automated surveying tools. Likewise, when we say that a model was still being offered as late as the mid-70s, this is only because they still had inventory that they hadn’t been able to sell.
Click on the image for a close-up of the scales for this rule. Note front and back scales are denoted A B F G, adjusted for steam pipe calculations on the front and water pipe calculations on the rear. Why K&E chose only to sell the Horsepower rule is unknown, but all such rules are similar in style and function. The horsepower rule is the most common; however, as well as the longest selling, sold by Stanley until approximately 1931.
The Model 4139 Cooke Radio Rule – Showing the front side of my more recent sample of two, this slide rule has a 1954 serial number. Significant in that it exhibits the model number and the rounded Cooke Radio emblem, which the earliest Cooke rules did not have, as well as the exposed mahogany edges. Decimal placement is more critical than in most slide rule usage cases, since many of the units are typically used with prefixes. As such, the capacitance could very well be in micro-farads, the inductance in micro-henries, operating on any number of kilo-cycles, yielding a reactance in kilo- or -mega-cycles .
Weinbach never let go the idea that K&E was making money off of his technology without compensation. Robinson estimates the total profit loss to Weinbach was around $190,000, which was a very large amount of money at https://hookupranking.org/ that time. Of course that figure comes from the fact that the Model 4081 Deci-Trig, which Weinbach claimed also used his decimal-based trig scales, had become their best seller and would remain so for decades later.
The previous owner has circled a few numbers in ink on the internal scales to facilitate a repeated calculation he must have been making, but this is minor and insignificant to the overall importance of this rule. The scales on the outer frame Have some chips and browning. The instructions on the base are nice as can be seen in the pics, The box is nice noting a few scratches and some loses to the finish. I only used a slip stick for a few years before hand-held digital calculators were introduced .
At this point, we turn to short-lived slide rules that never appeared in a K&E catalog. Most such rules are custom-made in small quantities, therefore rare, and likely never meant to be listed in a catalog. But K&E was often known to produce rules between catalog years that simply failed to sell for whatever reason.