In the early 90's, a steadily growing group of interested visitors gathered yearly around the impressive stand of slide rule collector IJzebrand Schuitema at the Utrecht Collectors Fair.

 

That was the start of what we now call the "Circle", a group of friends who share one passion: the collecting of slide rules.
Not only the search for ancient and special specimens is our goal, but also the  acquiring and sharing of information and documentation about this unique branch of industrial archeology.

Collecting as a hobby

For slide rules there exists a clearly demarcated era of production, from about 1625 to 1975. Let us not assume that a collector can ever call his collection complete. Hundreds of makers and manufacturers are known, together accounting for tens of thousands of models and types. Some well-known brands are Aristo, Faber-Castell and Nestler from Germany, Blundell-Harling from England, and Pickett and Keuffel & Esser from the USA.
Every collector will feel the need, at some time, to specialise in a particular brand, a special application area, or a distinctive type of construction.
Slide rule collectors often have adjoined areas of interest, like addiators or other mechanical calculators, drawing instruments like planimeters or compasses, or even stamps with the slide rule theme. The members of the Dutch Circle therefore represent a large diversity of interests.
As happens in any group of collectors, the social contacts between members turn out to be at least as important as the object of collecting itself.

Expansion of the Scope of the Dutch Circle
During the yearly meeting of December 2004, the decision was taken to expand the focus of the Circle formally, changing the name into:

"Kring Historische Rekeninstrumenten"
or in English:
"Dutch Circle for Historical Calculating Instruments"

This has been implemented during 2005.
The website stays for the time being at www.rekenlinialen.org, and will be renamed later. Also the logo will be adapted.

The following text describes the new definition of the Dutch Circle:

 

Dutch Circle for Historical Calculating Instruments

consisting of connoisseurs, collectors and researchers of historical calculating instruments 
at large, like slide rules, mechanical and electronic calculating machines, sectors, 
calculating tables, abaci, planimeters, compasses and other drawing instruments, 
plotting and measuring scales, and other calculating devices.

The focus of interest is on history, design, construction, production, collecting and 
restoration, but also applications, numerical techniques, and usage of the many types of 
calculating instruments which were the tools of scientists, technical professionals and 
other users in the past.

The mission of the Kring is:

	Mutual support of kring members in their pursuits,
	Promotion of public knowledge and awareness of the historical interest of  calculating instruments.

The Kring communicates primarily in the Dutch language.

The Kring evolved end 2004 from the Dutch Circle of Slide Rule Collectors
(Nederlandse kring van Verzamelaars van Rekenlinialen),

and has also welcomed some members of the former (Dutch) Society for
Historical Office Equipment Mercurius.

Top of page