## Circular slide rule based on Bürgi’s Logarithm Tables of 1620

The book *The Construction of Mathematics: The Human Mind’s Greatest Achievement* includes creation of tables of the logarithm function by the Swiss craftsman, engineer, and mathematician Jost Bürgi around 1600 CE, with delayed publication in 1620. The book includes the title page of Bürgi’s tables, then explains that the black numbers of the inner ring are on a logarithmic scale.

Due to that feature, two copies of that ring of numbers can be arranged in nested fashion depict a circular slide rule.

Bürgi did not realize this, or rather, there is no evidence that he did. Instead, William Oughtred invented the circular slide rule two years later, in 1622.

We couldn’t rest until we had implemented the circular slide rule based on Bürgi’s title page. For an authentic look, we created with Photoshop two differently sized copies of the black ring of numbers of Bürgi’s title page. The resulting rings were encased in Lexan and connected by a center bolt. It is fun to multiply and divide numbers by rotating the inner, smaller disk, all the time thinking that this is based on the work of genius done almost 400 years ago.

## Updated edition of book The Construction of Mathematics

A few readers of the book *The Construction of Mathematics: The Human Mind’s Greatest Achievement *had suggested that the discussion of Wittgenstein’s approach for the resolution of philosophical questions, which is central to the arguments of the book, be expanded. The updated edition released in January 2018 contains the desired additional explanations. At the same time, some minor corrections have been made.

## Effective Logic Computation Book Re-release

We now have re-released the revised edition in a low-cost print version. In some sense it is a companion book of the Matroid Decomposition book. Indeed, the theory of logic computation developed in the book relies on various concepts of matroid theory, in particular matroid decomposition. For details about the book, see the More Books page.

## Interview about Construction of Mathematics book

*CS News *of the University of Texas at Dallas has conducted an extended interview about the Construction of Mathematics book.

## Lecture Tour in Germany and Italy 2017

In May/June 2017, we will visit several universities and research institutes in Germany and Italy to deliver the lecture “Wittgenstein’s Philosophy and the Creation vs. Discovery Question of Mathematics.”

The lecture covers key points of the just-published book *The Construction of Mathematics: The Human Mind’s Greatest Achievement. *A discussion period is scheduled after the lecture.

The lecture is tailored for the general public and everyone is welcome to attend. No mathematical knowledge is necessary or assumed. For the location of the lecture hall and any other information, please contact the organizer of the university/institute for details.

Here is the schedule.

**Technical University of Munich (TUM), Garching, Germany
**Date: Tuesday May 9, 2017

Time of lecture: 6-7 pm (18:00-19:00)

Organizer: Prof. P. Gritzmann

**University of Erlangen-Nuremberg, Erlangen, Germany
**Date: Thursday May 11, 2017

Time of lecture: 4:15-5:15 pm (16:15-17:15)

The lecture is part of the workshop Johann Radon Lecture 2017. The workshop starts at 1pm (13:00).

Location: Felix Klein Building, lecture hall H13

Organizer: Prof. R. Schulz

**University of Cologne, Cologne, Germany**

Date: Wednesday May 17, 2017

Time of lecture: 4:30-5:30 pm (16:30-17:30)

Organizer: Prof. M. Juenger

**Technical University, Berlin, Germany**

Date: Monday May 29, 2017

Time of lecture: 4:00-5:00 pm (16:00-17:00)

Location: MA 041

Organizer: Prof. Martin Skutella

**University of Magdeburg, Magdeburg, Germany**

Date: Thursday June 1, 2017

Time of lecture: 5:00-6:00 pm (17:00-18:00)

Location: G03-106

Organizer: Prof. V. Kaibel

**Istituto di Analisi dei Sistemi ed Informatica “Antonio Ruberti” (IASI CNR), via del Taurini 19, Rome, Italy**

Date: June 5

Time of lecture: 11:30

Organizer: Prof. G. Rinaldi