Is that a slide rule in your pocket?
In the Yahoo ISRG Group, the question often arises of how to carry a 10 inch slide rule, as such a rule is too long for a breast pocket.
In Europe we use a bag, but many American students did not carry bags on campus: they walked around with a pile of books and notebooks. So where do you leave a 10 inch slide rule?
Ring binder Pouches
Some slide rules come with pouches that can be modified to be included in a ring binder (figure 2).
![Acu-Math Student Mannheim]](https://lh6.googleusercontent.com/mh1rZxVrfestzS5E1okt-rWmQOVUwGamMLpvA1aYZvUXYFuHpg1zQi-AkmkvDcvbw4oJkDUDLc0LRxUEHO8DhA9QJHe1r4LWdA2NTayiJkB_MASo=w1280)
Figure 2: Ring binder holes in the pouch of an Acu-Math Student Mannheim
Belt loops
Especially in the USA, cases for slide rulers have been made with a loop that can be used to hang the whole thing on your belt (figure 3,4, 5). But even in the 1950s it was considered “uncool”[1] and the use of the “belt loop” was limited.
According to ISRG members, the loop was sometimes used to hang a slide rule on a coat rack.
The case of a Load Adjuster has a loop that is probably also intended to hang it somewhere in an aeroplane (figure 3). After all, the Load Adjuster is not supposed to leave its aircraft.
Figure 3: The “belt loop” of a Pickett Cleveland Institute of Electronics slide rule and a loop on a pouch of a Load Adjuster.
More images of students wearing a slide rule on a belt loop:
Royal purple (Kansas State College year book) 1949, page 41
The Rollamo (University of Missouri School of Mines and Metallurgy yearbook) 1958, pages 9, 13 and 31
Royal purple (Kansas State College year book) 1959, page 50
The Amplifier (Montana School of Mines) vol. 6, no.3, Dec 11, 1959, page1
Carrollton High School, Georgia, Yearbook 1959 , page 82 (cited in Skid Stick 57, October 2017, page 13)
We don't know if using a belt loop in these pictures was spontaneous, or staged to convey a stereotype of the engineer.
In later years, it was used for depicting stereotypical engineers, see e.g. Skid Stick 58, Jan 2018, page 10
The belt loop also appeared in cartoons like one from IIT Tech New, April 1948 and one from Michigan Technic, May 1948 (courtesy IRSM)
Figure 4: A Japanese-American student during fieldwork in Nebraska, November 10, 1942, Online Archive of California
Figure 5: An engineer with a “belt loop”. The Cincinnatian, University of Cincinnati, OH, 1966, page 432
Trouser pockets.
Dieter Von Jezierski gives a quote from Josef Adalbert Sedlacek [Sedlaczek] from about 1820:
“It is said that the rule of the slide rule in England is so widespread that no tailor makes a pair of trousers without a pocket just for carrying a sliding rule.”[2]
I have no original source for this quote.
Adam Burg[3] discusses English “Taschen-Schieberlinealen” of 10 inches in 1830, but does not mention any trousers.
Léon Lalanne also remains vague about which clothing contained a slide rule pocket:
“... Règle a calcul ou règle glissante (Sliding Rule) ... Aussi cet instrument est-il devenu, dance le Royaume-Uni, d'un usage si général, que beaucoup d'ouvriers, the contremaîtres et même de commerçants , d'ingénieurs et de fabricants le portent constamment dans une poche longue dont leur vétement est muni, and que l'on appelle poche de la règle.”[4]
American campus journals[5] and year books contain advertisements for “campus cords with a slide rule pocket”. These are corduroy trousers that were popular on campuses in the Middle and West of the USA during a large part of the 20th century. There are no clear images of the advertisements, but Deirdre Clemente[6] does provide a photograph showing a student in “campus cords”. On his right leg an elongated pocket can be recognized, as we seen on carpenter's trousers.
Even today, “Men's trousers with slide rule pocket” are sold. The attached photo shows that the “slide rule pocket” is too narrow for most slide rules with a pouch. I would not put a slide rule in a pocket without the pouch, because you would easily lose the cursor.
This advertisement is most likely confusing slide rules with folding rulers, for which trouser leg pockets are commonly used.[7]
Would that also have happened in ads for American campus cords?
Fig. 6: “Men's tough trousers with slide rule pocket”, Ebay, May 2018, mtandme, UK
References
The Illinois Technograph, December 1935, page 6
Dieter Von Jezierski, “Slide Rules: A Journey Through Three Centuries”, Astragal Press, 2000, page 16
Adam Burg, “Über die Einrichtung und Anwendung des bei den englischen Mechanikern und Maschinenarbeitern gebräuchlichen Schieberlineals(Sliding rule), mit welchem sie sämmtliche, auf ihre Arbeiten Bezug habenden Rechnungen sehr leicht und schnell ausführen”, Jahrbücher k.k. polytechnischen Institutes in Wien, 16 (1830) page 117
Léon Lalanne, “Règle à calcul à enveloppe de verre”, advertisement in Revue de l'instruction publique en France et dans les pays étrangers, Paris, May 15, 1851.
The Michigan Daily, 27(19) Oct 24, 1916, p.5; The Oredigger, Colorado School of Mines, 11(18), Jan 27, 1931; page 2; The Oredigger, 15(7), November 3, 1934, page 3
Deirdre Clemente, “Dress Casual: How College Students Redefined American Style”, UNC Press Books, 2014, page 52
Ann Revenaugh Hemken, “The development and use of bib overalls in the United States, 1856-1945”, Master Thesis Iowa State University, 1993, pages 5, 25 and 27