Fred’s Head from APH, a Blindness Blog

Fred’s Head, offered by the American Printing House for the Blind, contains tips, techniques, tutorials, in-depth articles, and resources for and by blind or visually impaired people. Our blog is named after the legendary Fred Gissoni, renowned for answering a seemingly infinite variety of questions on every aspect of blindness.

(See the end of this page for subscribing via email, RSS, browsing articles by subject, blog archive, APH resources, writing for Fred's Head, and disclaimers.)



Thursday, August 13, 2015

How did you do arithmetic before the electronic calculator?

afb tactile slide rule on red vinyl record

Our object this week is an interesting artifact that most students today will not recognize, both for its tactile form and its outdated function.  A slide rule was an analog calculator used commonly by engineers and architects before the invention of the electronic calculator to do all sorts of mathematic and algebraic functions.   

Most were in the form of a sliding ruler, with several rulers set inside each other.  By sliding one value to a position lining it up with another, you could quickly find an answer on a separate part of the rule.  There were also circular slide rules, designed to take up less space.  

 This tactile version of the traditional circular slide rule was introduced by the American Foundation for the Blind in 1946.  It was made from a traditional phonograph record, fitted with a pair of rotating pointers. The scales were marked on the circumference of the disk in a series of raised dots.  

 We have two examples in our collection, a black vinyl version more typical of photograph records, and this one, produced in a fancy transparent red that was sometimes used for novelty records.  This one was used by Frank J. Healy, a student of the Oregon School for the Blind who later became Corporations Commissioner for the State of Oregon.

No comments:

Subscribe to receive posts via email

* indicates required

Browse Articles by Subject

Follow us on Twitter


Write for us

Your input and support in the evolution of Fred's Head are invaluable! Contact us about contributing original writing or for suggestions for updating existing articles. Email us at


The American Printing House for the Blind (APH) makes every attempt to ensure the accuracy and reliability of the data contained in the Fred's Head articles; however, APH makes no warranty, guarantee, or promise, expressed or implied, concerning the content or accuracy of the information provided in Fred's Head. APH does not endorse any technique, product, device, service, organization, or other information presented in Fred's Head, other than products and services directly offered by APH.

The products produced by the American Printing House for the Blind are instructional/teaching materials and are intended to be used by trained professionals, parents, and other adults with children who are blind and visually impaired. These materials are not intended as toys for use by children in unstructured play or in an unsupervised environment.

The information and techniques contained in Fred's Head are provided without legal consideration (free-of-charge) and are not warranted by APH to be safe or effective. All users of this service assume the risk of any injury or damage that may result from the use of the information provided.

Information in Fred's Head is not intended as a substitute for professional advice or treatment. Consult your physician before utilizing information regarding your health that may be presented on this site. Consult other professionals as appropriate for legal, financial, and related advice.

Fred's Head articles may contain links to other websites. APH is not responsible for the content of these sites.

Fred's Head articles created by APH staff are (C) copyright American Printing House for the Blind, Inc. You must request permission from APH to reprint these articles. Email to request permission.

Any submissions to Fred's Head should be free of copyright restrictions and should be the intellectual property of the submitter. By submitting information to Fred's Head, you are granting APH permission to publish this information.

Fair Use Notice: This website may contain copyrighted material whose use has not been specifically authorized by the copyright holder(s). This site is operated on the assumption that using this information constitutes 'fair use' of said copyrighted material as provided for in Section 107 of U.S. Copyright Law.

Opinions appearing in Fred's Head records are solely those of the contributor and do not necessarily reflect the views of the American Printing House for the Blind.