Index by Purpose

An image of various slide rules from the collection of the Division of Medicine and Science at the National Museum of American History.

While many slide rules were made as general calculating instruments, for multiplying numbers and solving equations with squares, cubes, trigonometric functions, and logarithms, many others were made to ease the calculations associated with a specific task. Click on items in the list below to see rules in the collection with an identifiable specialized purpose. For comparison, a few illustrative examples of all-purpose slide rules are shown under the link to General Calculation.

AccessibilityEngineering, ElectricalNavigation
AgricultureEngineering, GeneralNovelty Forms
AstronomyFirefightingPromotion & Sales
Business & Office WorkGaugingShipping
CarpentryGeneral CalculationStatistics
ComputingGovernmentSurveying
ConstructionManufacturingTelevision
Conversion ChartsMetalworkingTransportation
EducationMeteorologyWagering
Engineering, AeronauticalMilitary Applications 

Perrygraf Machining Calculator Slide Rule for LeBlond

This yellow and white rectangular paper rule has a white paper slide and is held together with four metal rivets. On the front, the top scales allow one to calculate the revolutions per minute for a given work diameter and surface speed.
Description
This yellow and white rectangular paper rule has a white paper slide and is held together with four metal rivets. On the front, the top scales allow one to calculate the revolutions per minute for a given work diameter and surface speed. The bottom scales allow calculation of the time in minutes and seconds for a given feed rate, length of cut, and R.P.M. The back of the instrument has tables for converting from fractions to decimals and for finding the suggested carbide surface speed of a lathe for different materials.
Perrygraf Corporation, described in 1979.3074.03, made this instrument in 1949 for the R. K. LeBlond Machine Tool Company of Cincinnati. A salesman could attach his card to the back of the calculator and give it to a client. Richard K. LeBlond (1864–1953) began making machines in 1887 and became known for the quality of his lathes in the 1890s. Products included lathes for manufacturing bicycles and automobile crankshafts. The company employed 1,200 workers and made a mammoth lathe for boring artillery during World War II. In 1981 Makino Corporation of Japan purchased the company. The factory in Cincinnati is now Rookwood Pavilion shopping center.
Perrygraf slide rules in the collection include: 1983.3009.04, 1983.3009.05, 1983.3009.06, 1987.0108.03, 1988.0323.01, 1988.0325.01, and 1992.3103.01.
References: Tom Wyman, "Slide Chart Calculators – A Modest Proposal," Journal of the Oughtred Society 13, no. 1 (2004): 6–10; Kenneth L. Cope, American Lathe Builders: 1810–1910 (Mendham, N.J.: Astragal Press, 2001), 89; Tony Griffiths, "LeBlond - USA," Machine Tool Reference Archive, http://www.lathes.co.uk/leblond/.
Location
Currently not on view
date made
1949
maker
Perry Graf Corporation
ID Number
1992.3103.01
nonaccession number
1992.3103
catalog number
1992.3103.01

Keuffel & Esser 68-1555 Doric Duplex Slide Rule

This turquoise plastic 5-inch duplex slide rule has DF, D, and L scales on the front of the base and CF, CI, and C scales on the slide. The top of the base is marked: PAT. PEND.; CELANESE CELCON; MADE IN U.S.A. The right end of the slide is marked: DORIC (/) K & E CO.
Description
This turquoise plastic 5-inch duplex slide rule has DF, D, and L scales on the front of the base and CF, CI, and C scales on the slide. The top of the base is marked: PAT. PEND.; CELANESE CELCON; MADE IN U.S.A. The right end of the slide is marked: DORIC (/) K & E CO. On the back, the base has K, A, D, and T scales, and the slide has B, ST, and S scales. The indicator is plastic, and the endpieces are metal.
The rule fits in a black leather sheath, embossed with the K+E logo and imprinted in gold: CELANESE CELCON (/) DESIGNED FOR THE ENGINEER ∙ ENGINEERED FOR THE DESIGNER. The sheath and a leaflet, "How to Take Care of Your Slide Rule," fit in a cardboard box covered with green vinyl. The end of the box bears a label marked: K+E (/) 68 1555 (/) POCKET SLIDE RULE (/) LEATHER SHEATH (/) MADE IN U.S.A.; TRADE MARKS ®. It is also marked there: OLD (/) 4168.
According to the donor, “The Celcon rule is significant because this is the first use of this very durable engineering plastic or resin in a slide rule. This durable material, trademarked Celcon, was an American invention made in the laboratories of the Celanese Corporation.” The donor was corporate research director at Celanese Corporation before he retired in December 1981. The 1962 Keuffel & Esser Catalog lists a 5" slide rule with model number 68 1555 made of “Ivorite.” The instrument is shown in the 1964 and 1967 catalogs (still as made of “Ivorite”) and called the “Doric.” It is not shown in the 1972 catalog. Celanese Corporation first used the term “Celcon” to refer to a thermoplastic in 1945, and trademarked the term in 1960. It seems likely that this rule was produced especially for Celanese Corporation in the period 1962–1971. This was the only time K&E manufactured a slide rule that was not white.
References: Joseph L. Soper, "The Celanese Celcon Promotional Slide Rule," in K&E Salisbury Products Division Slide Rules (Pleasanton, Calif.: The Oughtred Society, 2007), 115; Clark McCoy, ed., "K&E Catalogs and Price Lists for Slide Rules," http://www.mccoys-kecatalogs.com/KEmain.htm.
Location
Currently not on view
date made
1962-1971
maker
Keuffel & Esser Co.
ID Number
1993.0357.01
accession number
1993.0357
catalog number
1993.0357.01

Instruction Manual for Keuffel & Esser Polyphase Duplex Pocket Slide Rule

This 70-page booklet was received with 1993.0357.01. The book explains how to operate model 68–1555, which was model 4168 before 1962. Its citation information is: Keuffel & Esser Polyphase Duplex Pocket Slide Rule . . . Instruction Manual, 2nd ed.
Description
This 70-page booklet was received with 1993.0357.01. The book explains how to operate model 68–1555, which was model 4168 before 1962. Its citation information is: Keuffel & Esser Polyphase Duplex Pocket Slide Rule . . . Instruction Manual, 2nd ed. (New York: Keuffel & Esser Co., 1947). Presumably only the cover and illustration of the slide rule were updated in the 1960s. Topics covered include: multiplication and division, proportion, squares and square roots and cubes and cube roots, and plane trigonometry. Answers are provided at the back.
Location
Currently not on view
date made
1960s
maker
Keuffel & Esser Co.
ID Number
1993.0357.01.01
accession number
1993.0357
catalog number
1993.0357.01.01

Dietzgen 1771 Redirule Simplex Slide Rule

This one-sided, five-inch white molded plastic rule has a plastic indicator with a hairline and plastic edges. A, D, and K scales are on the base, with B, CI, and C scales on one side of the slide and S, L, and T scales on the other side of the slide.
Description
This one-sided, five-inch white molded plastic rule has a plastic indicator with a hairline and plastic edges. A, D, and K scales are on the base, with B, CI, and C scales on one side of the slide and S, L, and T scales on the other side of the slide. The top and bottom edges are beveled, with a scale of 5 inches divided to 32nds of an inch on the top and a scale of 12.5 centimeters divided to millimeters on the bottom. The top of the base is marked (in red): No. 1771 REDIRULE ® DIETZGEN MADE IN U.S.A. Three screws for adjusting the rule are on the back of the instrument. The rule fits in a brown leather sheath marked: DIETZGEN. The sheath fits in an orange paper box marked on each end: DIETZGEN Redi-Rule ® (/) 5 INCH POCKET SLIDE RULE (/) Molded Plastic, Leather Sheath 1771. The rule was received with an instruction manual, 1993.0357.02.01.
According to records of the U.S. Patent and Trademark Office, Eugene Dietzgen Company began using the phrase REDIRULE to describe slide rules in 1944, applied for a trademark on the term in 1947, and received the trademark in 1953. According to Peter Hopp and Bruce Babcock, Dietzgen manufactured model 1771 of the Redirule or Redi-rule from 1941 to 1972. (Another Redirule, model 1776, had an additional six scales and metal endpieces.) Dietzgen's catalog for 1948–1949 describes model 1771 as "a real pocket companion" that "weighs no more than your pen."
References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 160; Bruce Babcock, "Dietzgen Catalog Matrix," Journal of the Oughtred Society 5, no. 2 (1996), http://sliderulemuseum.com/Manuals/Dietzgen_CatalogMatrix_BruceBabcock1996_chart.jpg; Dietzgen Redirule Instruction Manual (Chicago: Eugene Dietzgen Co., n.d.), http://sliderulemuseum.com/Manuals/M12_Dietzgen_1776_redirule_ref-P023.jpg; Ovid W. Eshbach and H. Loren Thompson, Self-teaching Instruction Manual: Dietzgen Decimal Trig Type Log Log Slide Rule (Chicago: Eugene Dietzgen Co., 1960), 107–108; http://sliderulemuseum.com/Manuals/Dietzgen_1734_Manual.pdf.
Location
Currently not on view
date made
1953-1972
maker
Eugene Dietzgen Company
ID Number
1993.0357.02
accession number
1993.0357
catalog number
1993.0357.02

Keuffel & Esser 4071-3 Polyphase Decitrig Duplex Slide Rule

This ten-inch mahogany duplex linear slide rule is almost completely coated with white celluloid. The frameless glass indicator has plastic edges. On one side, the base has K and A scales at the top and D and DI scales at the bottom. The slide has B, T, SRT, and S scales.
Description
This ten-inch mahogany duplex linear slide rule is almost completely coated with white celluloid. The frameless glass indicator has plastic edges. On one side, the base has K and A scales at the top and D and DI scales at the bottom. The slide has B, T, SRT, and S scales. Divisions of angles are indicated in decimal fractions. The left side of the slide is marked with the serial number 330508, with the number 508 printed on the left side of both parts of the base.
The other side of the rule has a DF scale on the top of the base and D and L scales on the bottom of the base. The slide has CF, CIF, CI, and C scales. The top of the base is marked in red: KEUFFEL & ESSER CO.; PATS. 2,500,460 2,168,056 2,170,144 PAT PEND.; MADE IN U.S.A. The right side of the slide is marked with the K&E logo, a copyright sign, and the model number, 4071-3. The instrument fits in an orange leather case with the K&E logo on the flap. Inside the flap is written in ink: H. R. L. (/) JULY '62.
Keuffel & Esser Company of New York sold this model from 1939 to 1967. The combination of scales on this example was sold beginning in 1955, and the model was renumbered in 1962 to 68-1502. Thus, the rule was probably manufactured between 1955 and 1962. The serial number is consistent with this dating.
The donor, Alfred E. Brown, was a research chemist for Celanese Corporation, which partnered with K&E in the 1960s to produce a special version of the 68-1555 slide rule (see 1993.0357.01). However, it is not known how this rule came into Brown's possession.
References: Clark McCoy, "Collection of Pages from K&E Catalogs for the 4071-3 Family of Slide Rules," http://www.mccoys-kecatalogs.com/KEModels/ke4071family.htm; Carl M. Bernegau, "Slide Rule" (U.S. Patent 2,168,056 issued August 1, 1939); Lyman M. Kells, Willis F. Kern, and James R. Bland, "Slide Rule" (U.S. Patent 2,170,144 issued August 22, 1939); Herschel Hunt, "Slide Rule" (U.S. Patent 2,500,460 issued March 14, 1950); Walter Shawlee II, Ted Hume, and Paul Ross, "Keuffel & Esser Co. Slide Rules," Sphere Research Corporation, http://www.sphere.bc.ca/test/ke-sliderule.html; "Alfred E. Brown Chemist," The Washington Post, March 19, 2004, http://www.washingtonpost.com/wp-dyn/articles/A9676-2004Mar19_2.html.
Location
Currently not on view
date made
1955-1962
date received
1993
maker
Keuffel & Esser Co.
ID Number
1993.0482.01
accession number
1993.0482
catalog number
1993.0482.01

Pickett N1010-T Duplex Slide Rule

This ten-inch aluminum linear slide rule is coated with white plastic (the "traditional" color). It has a nylon indicator and is held together with stamped aluminum squared posts. The front of the base has K, A, D, and DI scales, with B, ST, T, S, and C scales on the slide.
Description
This ten-inch aluminum linear slide rule is coated with white plastic (the "traditional" color). It has a nylon indicator and is held together with stamped aluminum squared posts. The front of the base has K, A, D, and DI scales, with B, ST, T, S, and C scales on the slide. The left end of the slide is marked: MODEL (/) N1010-T (/) TRIG. The right end of the slide bears the style of Pickett logo used between 1958 and 1962. The number 74 appears above the logo.
The back of the base has DF, D, DI, and L scales, with CF, CIF, CI, and C scales on the slide. The left end of the slide is marked: COPYRIGHT 1959 © (/) PATENT APPLIED FOR. The right end of the slide is marked: PICKETT & ECKEL, INC. (/) 272.
The slide rule fits into a clear plastic bag and then into an orange-brown leather case lined in clear plastic. The triangular Pickett logo is embossed below the slot for the case's flap, and there is a metal ring on the back of the case for attaching to a belt. The slide rule arrived in a white, black, red, and yellow cardboard box. The 1958-1962 Pickett logo is superimposed on a model of the atom on the box. The top and bottom of the box are marked with several of the instrument's selling points: lifetime accuracy, all metal permanence; select a handy pocket size rule too (/) matched for your convenience by Pickett; micro divided scales; world's most accurate; safety liner case; completely guaranteed; complete instruction manual; slider tension springs.
Inside the box are four pieces of paper: a welcome note from company president John W. Pickett, marked Form 247; care instructions for the rule, marked Form 543; a guarantee, which indicates this instrument has serial number 252372; and a promotional flyer on Pickett's "eye-saver" yellow color, marked Form 225-A. See 1993.0559.01.01 for an instruction manual received in the box. One end of the box is marked: Pickett SLIDE RULE (/) all metal • guaranteed (/) A PRODUCT OF AMERICAN ENGINEERING AND MANUFACTURING. The other end of the box has a product label, which notes the Model N-1010-T Trig Slide Rule has the: Approved Scale Arrangement for basic work in all fields (Schools, Business, Industry) where Log Log scales are not needed.
The logo, nylon indicator with flat lens, straight style of posts, and company addresses in Chicago and Alhambra, Calif., are all consistent with a date around 1960. However, according to the donor, the slide rule was given to him by his parents as a Christmas gift in 1944.
References: Alan Boardman, "Recollections of a Pickett Industries Employee," Journal of the Oughtred Society 16, no. 2 (2007): 8; Walter Shawlee, "Pickett Slide Rules," http://www.sphere.bc.ca/test/pickett.html; Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries, trans. Rodger Shepherd (Mendham, N.J.: Astragal Press, 2000), 75–76.
Location
Currently not on view
date made
ca 1960
maker
Pickett & Eckel, Incorporated
ID Number
1993.0559.01
accession number
1993.0559
catalog number
1993.0559.01

Pickett Trig Slide Rule Instruction Manual

This 64-page booklet was received with 1993.0559.01. Its citation information is: Maurice L. Hartung, How to Use . . . Trig Slide Rules (Chicago: Pickett & Eckel Inc., 1960). It sold separately for fifty cents.
Description
This 64-page booklet was received with 1993.0559.01. Its citation information is: Maurice L. Hartung, How to Use . . . Trig Slide Rules (Chicago: Pickett & Eckel Inc., 1960). It sold separately for fifty cents. Hartung was the University of Chicago professor who was closely associated with Pickett & Eckel in the company's early years and who wrote several instruction manuals for the firm's slide rules.
The booklet discusses slide rule operation, use of certain special scales, applications of trigonometry, and the principles underlying slide rules. Hartung focused on the operations of the instrument rather than on mathematical theory. There are problem sets at the end of each section, with answers in the back of the manual, and a few sets of "practical" (word) problems. Another copy of the booklet is scanned at http://sliderulemuseum.com/Manuals/M104_Pickett_HowToUseTrig_1960.pdf.
Reference: "Maurice Leslie Hartung," Mathematics Genealogy Project, http://www.genealogy.math.ndsu.nodak.edu/id.php?id=7964. Hartung received a life achievement award from the Illinois Council of Teachers of Mathematics in 1977, http://ictm.org/ictmawards/lifeachievement.html.
Location
Currently not on view
date made
1960
publisher
Pickett Industries
author
Hartung, Maurice L.
ID Number
1993.0559.01.01
accession number
1993.0559
catalog number
1993.0559.01.01

Keuffel & Esser 4088-5 Polyphase Duplex Slide Rule

This duplex linear slide rule is made of mahogany coated with celluloid. There are DF and D scales on one side of the base and K, A, D, and L scales on the other side. There are CF, CIF, and C scales on one side of the runner and B, S, T, and CI scales on the other side.
Description
This duplex linear slide rule is made of mahogany coated with celluloid. There are DF and D scales on one side of the base and K, A, D, and L scales on the other side. There are CF, CIF, and C scales on one side of the runner and B, S, T, and CI scales on the other side. The scales are 20 inches long (the "5" in the model number refers to a rule with scales 20 inches long) and closely divided. The indicator is made of glass with a plastic frame.
The base is marked: KEUFFEL & ESSER CO.N.Y.; PAT. JUNE 5. ’00; DEC. 22. ’08; MADE IN U.S.A. The runner is marked: 4088-5. The serial number, on the other side of the runner, is: 72287. The slide rule is stored in a dark brown cardboard and glued leather box.
Keuffel & Esser published catalogs in 1899, 1902, 1905, 1909, 1912, 1915, 1921, 1927, and 1936. Model 4088-2 (8 in.) and 4088-3 (10 in.) slide rules first appeared in the 1913 printing of the 1912 catalog (facing p. 304). Model 4088-5 was first mentioned in 1921 (p. 239) and then again in 1927 (p. 302). In 1927 and in the 1930s (but not in 1921), the front of the runner had a B scale in addition to the S, T, and CI scales. By 1936, the 4088-5 was replaced by the N4088-5 (p. 314). On this basis, the rule dates from between 1922 and 1935. Additionally, the donor reported that he received the slide rule from a friend in about 1930. The instrument sold for $20.00 in 1927. Compare this object to 318476 and 1986.0790.02.
References: Willie L. E. Keuffel, "Slide-Rule" (U.S. Patent 651,142 issued June 5, 1900) and "Slide-Rule" (U.S. Patent 907,373 issued December 22, 1908); Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 193; Clark McCoy, Keuffel & Esser Catalogs, http://www.mccoys-kecatalogs.com.
Location
Currently not on view
date made
1922-1936
maker
Keuffel & Esser Co.
ID Number
1994.0376.001
catalog number
1994.0376.001
accession number
1994.0376

Hemmi-Sun Mannheim Slide Rule

This small (4-inch) one-sided rule is bamboo with a metal backing, entirely covered with white celluloid. A magnifying glass indicator has a metal frame. There are A and D scales on the base. The slide has B and C scales on one side and S, L, and T scales on the other side.
Description
This small (4-inch) one-sided rule is bamboo with a metal backing, entirely covered with white celluloid. A magnifying glass indicator has a metal frame. There are A and D scales on the base. The slide has B and C scales on one side and S, L, and T scales on the other side. The lower edge of the base has a scale of centimeters divided to millimeters. The upper edge of the base has a scale of inches divided to thirty-seconds of an inch.
The D scale is marked at each end: Quot (/) +1; Prod (/) -1. The back of the slide rule is marked: "SUN" (between two drawings of the sun); HEMMI; MADE IN JAPAN. A brown leather case is stamped in gold on the flap: BAMBOO (/) SLIDE RULE (/) "SUN" (between two drawings of the sun) (/) HEMMI. Written in pen inside the flap is: BOB YINGLING.
According to the donor, a colleague used this slide rule in a training program at the American Brass Company Division of Anaconda Mining Company in Waterbury, Conn., in the 1940s. He used it for such problems as calculating the weight of samples from their volume and density.
Location
Currently not on view
date made
ca 1940
maker
SUN HEMMI JAPAN CF
ID Number
1995.0087.01
accession number
1995.0087
catalog number
1995.0087.01

Mannheim Slide Rule

This small, one-sided slide rule is made of wood. It has a white plastic layer on the front of both the base and the slide. The indicator is made from plastic. The base bears A, D, and K scales. The slide bears B, CI, and C scales. The scales are approximately 4-1/8 inches long.
Description
This small, one-sided slide rule is made of wood. It has a white plastic layer on the front of both the base and the slide. The indicator is made from plastic. The base bears A, D, and K scales. The slide bears B, CI, and C scales. The scales are approximately 4-1/8 inches long. The slide is slightly longer than the base. The back of the slide rule is bare boxwood and has no scales.
The instrument is marked on the slide: MADE IN (/) ENGLAND. It closely resembles the 4-inch Jiffy slide rule made by Unique Slide Rule Company of Brighton, England. Unique sold slide rules from about 1923 to 1975.
References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 229–231; "British Slide Rules," The Slide Rule Museum, http://sliderulemuseum.com/British.htm; David M. Riches, Mathematical Instruments: A Private Collection, http://www.mathsinstruments.me.uk/page14.html; Peter Hopp, Colin Barnes, and John Knott, "Unique Slide Rules," Journal of the Oughtred Society 6, no. 1 (1997): 32–44.
Location
Currently not on view
ID Number
1995.0087.02
accession number
1995.0087
catalog number
1995.0087.02

Dalton E-6B Dead Reckoning Computer by Jeppesen

In this instrument a white rectangular plastic sheet slides between two white discs that are held together with black plastic bars and metal grommets.
Description
In this instrument a white rectangular plastic sheet slides between two white discs that are held together with black plastic bars and metal grommets. The sheet is marked in green on both sides, with a polar grid and rectangular grid on one side and a polar grid on the other side. The front disc has scales for altitude computations at the top and for air speed computations at the bottom. The back disc has a scale to correct direction readings for wind and a scale for converting temperature readings from degrees Centigrade to Fahrenheit. The center of the back disc is clear for viewing the grid. A salmon plastic sheath stores the instrument.
The device is marked on the front: DALTON DEAD RECKONING COMPUTER (/) TYPE E-6B. It also is marked: WEEMS SYSTEM OF NAVIGATION (/) (A DIVISION OF JEPPESEN & CO.) (/) DENVER, COLORADO; PAT. NO. 2,097,118. The grid is marked in pencil: FL[IGH]T OFF COURSE (/) 2 MILES/SQUARE. The back of the disc is also marked in pencil. The three lines in the clear part of the disc are illegible, but below the temperature conversion scale, the marks read: 3.5° F/1000'. A ring at the top of one black plastic bar is marked: U.S. PAT. 3,112,875.
Naval Reserve pilot Philip Dalton, in consultation with navigation instructor Philip Van Horn Weems, developed the Dalton dead reckoning computer for the U.S. Army Air Corps and received a patent in 1937. The device was widely used during World War II.
After the war, many manufacturers in the United States and Europe made the E-6B. Elrey Borge Jeppesen, a pilot for what became United Airlines, founded his company in 1934 and moved it to Denver in 1941. Jeppesen & Co. made aeronautical charts and navigational tools and guides. It became a subsidiary of Boeing in 2000. The patent number on the back of this object refers to the design of the computer with the gridded rectangular sheet and two discs. The patentees were employed by Felsenthal Instruments Co., which frequently supplied companies with the plastic for manufacturing Dalton computers in the 1950s and 1960s.
The donor purchased this object around 1965 and used it for about two years in airplane navigation.
References:
Paul McConnell, "Some Early Computers for Aviators," Annals of the History of Computing 13, no. 2 (1991): 155–177, on 156. Philip Dalton, "Plotting and Computing Device" (U.S. Patent 2,097,116 issued October 26, 1937).
Ben Van Caro and Burton L. Fredriksen, "Computer Slide Construction" (U.S. Patent 3,112,875 issued December 3, 1963). "E6B," http://en.wikipedia.org/wiki/E6B.
"Jeppesen," http://en.wikipedia.org/wiki/Jeppesen.
"On the Beam," advertisement for Dalton Dead Reckoning Computer, Felsenthal Plastics, Flying 35, no. 2 (August 1944): 10.
Paul Sanik, "U.S. Army Air Corps Aerial Dead Reckoning type E-6B," Journal of the Oughtred Society 6, no. 2 (1997): 32–34 .
Location
Currently not on view
date made
1960s
maker
Jeppesen & Co.
ID Number
1995.0087.03
accession number
1995.0087
catalog number
1995.0087.03

Pickett 904-ES Decimal Keeper Duplex Slide Rule

This aluminum duplex slide rule has a yellow coating and a clear plastic indicator. The "ES" in the model number refers to the rule's "Eye Saver" yellow color. The rule and indicator are held together with aluminum braces that have protruding grooves.
Description
This aluminum duplex slide rule has a yellow coating and a clear plastic indicator. The "ES" in the model number refers to the rule's "Eye Saver" yellow color. The rule and indicator are held together with aluminum braces that have protruding grooves. The front of the rule has K, A, DF, D, and L scales, with CF, S, T, CI, and C scales on the slide. The scales are 9-1/2 inches long. The back of the rule has a D* scale, with T*, S* Cl*, and C* scales on the slide. Instead of covering the typical one decade of C and D scales, the scales with asterisks cover twenty decades, from 1010 to 10-10. These scales helped inexperienced users keep track of the decimal point. They performed their calculation first on the back, to determine the order of magnitude, and then a second time on the front, to make the answer precise to three significant figures.
The front of the slide is marked: MODEL 904-ES (/) TRIG AND (/) DECIMAL KEEPER (/) SPEED RULE. A Pickett logo is at the other end of the slide, with the number 47 printed above the logo. The back of the rule is marked: PATENT (/) APPLIED FOR; DECIMAL KEEPER; PICKETT & ECKEL, INC. (/) CHICAGO 3, ILL. - ALHAMBRA, CAL. The logo on this rule is that used by Pickett from 1958 to 1962. The shape and material of the cursor and the braces suggest a date of 1957–1959. Hence, the object appears to have a rough date of 1958–1959.
The donor patented an "automatic decimal point slide rule" and assigned the patent to Pickett. He also distributed Pickett slide rules through his own mail order firm of Devonics, Inc.
The rule was received in a plastic bag. For somewhat related documentation, see 1995.0126.04. See also Lawrence J. Kamm, "Automatic Decimal Point Slide Rule" (U.S. Patent 2,893,630 issued July 7, 1959).
References: Dieter von Jezierski, Slide Rules: A Journey Through Three Centuries (Mendham, N.J.: Astragal Press, 2000), 75–76, 100; Ron Manley, "Pickett 904-ES – Trig and decimal keeper," http://www.sliderules.info/collection/10inch/090/1096-pickett-904.htm; "Slide Rule Dates and Time-Lines," http://sliderulemuseum.com/SR_Dates.htm.
Location
Currently not on view
date made
ca 1958-1959
maker
Pickett & Eckel, Incorporated
ID Number
1995.0126.01
accession number
1995.0126
catalog number
1995.0126.01

Pickett N901-ES Simplex Slide Rule

This aluminum slide rule is coated in "Eye Saver" yellow, as denoted by the model number. It is held together with aluminum braces; the indicator is nylon (also denoted by the model number) with three metal screws.
Description
This aluminum slide rule is coated in "Eye Saver" yellow, as denoted by the model number. It is held together with aluminum braces; the indicator is nylon (also denoted by the model number) with three metal screws. The front of the rule has A, D, and L scales, with B, CI, and C scales on the slide. The scales are about ten inches long. The slide and the top of the rule are both marked: MODEL N901-ES (/) SIMPLEX (/) MATH RULE. The other end of the slide bears the Pickett logo and the mark: MADE IN U.S.A.
The back of the rule has X and D* scales, with Y and C* scales on the slide. The top of the rule is marked: PICKETT, INC.; MODEL N901-ES; SIMPLEX MATH RULE. The bottom of the rule is marked: COPYRIGHT 1965; PICKETT, INC. SANTA BARBARA. CALIF.; MADE IN U.S.A.
The rule fits in a black leather sheath. The sheath was received in a green, white, and black cardboard box. One end of the box is marked: PickETT (/) 901-ES (/) ELEMENTARY MATH. It also is marked: about this rule: (/) 10 scales are keyed to (/) new math. Aids under- (/) standing of addition, (/) subtraction, multiplica- (/) tion, division and Base 10 (/) relationships. Grade 3 up. The inside of the box top flips up for display. The box slides into a green, white, and black cardboard cover. The top and sides of the box cover are each marked: PickETT; ALL METAL (/) SLIDE (/) RULE.
The box also contains a yellow paper slide rule guarantee and registration card. The object's serial number is A1216143. A 48-page instruction manual by Maurice L. Hartung is stored separately (1995.0126.02.01).
The X and Y scales were used for addition and subtraction and were unique to Pickett. Donor Lawrence J. Kamm conjectured that Hartung, a mathematics professor at the University of Chicago, recommended they be added to this product. According to Kamm, Hartung encouraged company cofounder Ross Pickett to market its slide rules only to schoolchildren. In order to provide scientists and engineers with access to rules such as the Decimal Keeper (1995.0126.01), Kamm opened a mail-order business that distributed Pickett's products.
References: Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: The Astragal Press, 1999), 209–210; Maurice L. Hartung, Complete, Semi-Programmed Teaching Instructions for the Use of Elementary Simplex Math Slide Rule (Santa Barbara, Calif.: Pickett, Inc., 1965); accession file; International Slide Rule Museum, "Pickett," http://sliderulemuseum.com/Pickett.htm.
Location
Currently not on view
date made
after 1965
date received
1995
maker
Pickett & Eckel, Incorporated
ID Number
1995.0126.02
accession number
1995.0126
catalog number
1995.0126.02

Pickett Decimal-Keeper Slide Rule Instructions

This twelve-page booklet was received with 1995.0126.01. Titled "How To Use Decimal-Keeper Slide Rules," it is another of the instruction manuals Maurice L. Hartung wrote for Pickett & Eckel, Inc., a slide rule manufacturer based in Chicago and Alhambra, Calif.
Description
This twelve-page booklet was received with 1995.0126.01. Titled "How To Use Decimal-Keeper Slide Rules," it is another of the instruction manuals Maurice L. Hartung wrote for Pickett & Eckel, Inc., a slide rule manufacturer based in Chicago and Alhambra, Calif. Hartung explained how Pickett had reduced the scales on slide rules in the Decimal-Keeper line so that one ten-inch Decimal-Keeper became equivalent to twenty ordinary ten-inch linear slide rules. These reduced scales are the scales marked with asterisks on Decimal-Keeper slide rules.
There are also instructions for locating the proper section of the scale, carrying out division, computing trigonometric functions, calculating roots, finding logarithms, and adjusting and cleaning the slide rule. The booklet is undated. Separately, it sold for 50 cents and had model number M-17.
Location
Currently not on view
date made
ca 1960
maker
Pickett & Eckel, Incorporated
ID Number
1995.0126.04
accession number
1995.0126
catalog number
1995.0126.04

Charpentier Calculimetre Multidisc Circular Slide Rule

This brass circular slide rule is the size and shape of a pocket watch. The base is a silver-colored disc surrounding a rotating brass ring.
Description
This brass circular slide rule is the size and shape of a pocket watch. The base is a silver-colored disc surrounding a rotating brass ring. The silver-colored indicator, which moves the brass ring and a forked pointer screwed to the center of the instrument, is attached to a small suspension ring. The indicator extends around the back of the instrument for use in reading the scales inscribed there.
Three scales are on the front: two logarithmic scales on the outermost rings (the equivalent of D and C scales on a linear slide rule) and a two-part scale for square roots around the silver-colored circle at the center (corresponding to the A scale on a linear slide rule). Around the center is engraved: CALCULIMETRE G. CHARPENTIER; BREVETÉ S.G.D.G. The serial number 35 is engraved below "Charpentier." The back of the instrument bears a scale of equal parts, a logarithmic scale, and an innermost scale of equal parts. The indicator arm is engraved: FRANCE.
Around 1882, G. Charpentier patented this design in France (as indicated by the "breveté" mark) and Great Britain. Several French instrument makers manufactured the device. In the United States, the Calculimetre was retailed for $5.00 by Keuffel & Esser from 1895 to 1927 and by Dietzgen from 1904 to 1931. According to the donor, John W. Olson, a Wall Street investment banker and collector of "unusual items" named Edward Hamilton Leslie purchased this slide rule around 1925.
References: Robert K. Otnes, "The Charpentier Calculator," Journal of the Oughtred Society pilot issue, vol. 0, no. 0 (1991): 9–11; Florian Cajori, A History of the Logarithmic Slide Rule and Allied Instruments (New York: Engineering News Publishing Company, 1909), 94; Peter M. Hopp, Slide Rules: Their History, Models, and Makers (Mendham, N.J.: Astragal Press, 1999), 81, 161, 193; Catalogue & Price List of Eugene Dietzgen Co., 7th ed. (Chicago, 1904), 174; Catalogue of Keuffel & Esser Co., 33rd ed. (New York, 1909), 307.
Location
Currently not on view
date made
ca 1925
ID Number
1995.0261.01
accession number
1995.0261
catalog number
1995.0261.01

Multi-Slide Slide Rule & Mathematical Tables

This yellow, red, black, and white slide rule has a cardboard front and back, held together with metal grommets along the top and bottom. A paper slide and a clear plastic cover fit inside the cardboard. Three red hairline indicators are on the plastic.
Description
This yellow, red, black, and white slide rule has a cardboard front and back, held together with metal grommets along the top and bottom. A paper slide and a clear plastic cover fit inside the cardboard. Three red hairline indicators are on the plastic. The front of the rule bears A, D, and K scales, with B, CI, and C scales on the front of the slide. The scales are 8-1/2 inches long. The front also has a vertical window for reading off four-place logarithms. There are tables for decimal equivalents and slide rule settings.
The back of the rule has A and D scales, with S, L, and T scales on the back of the slide. There are tables for trigonometric formulae and mathematical formulae, and a vertical window for reading off natural trigonometric functions.
The front of the rule is marked: SLIDE RULE & MATHEMATICAL TABLES (/) MIGHTY MITE (/) THERMAL CONTROLS; MECHANICAL INDUSTRIES (/) PRODUCTION COMPANY (/) 217 ASH ST. • AKRON 2, OHIO. The back of the rule is marked: Copyright 1945, Multi Slide Instrument Corp., Chicago, Ill.—Pat. Pending (/) Reproduction in whole or part will be prosecuted.
The rule is housed in an envelope that also contains a sheet of instructions and two samples of Mighty Mite Thermal Controls. The front of the envelope bears the same information about the distributor, Mighty Mite, which appears on the front of the rule. However, the address for Mechanical Industries is given as 217-233 Ash St. The front is also marked: Multi (/) SLIDE (/) RULE. The back of the envelope describes the company's single- and dual-action thermal controls.
The larger silver dual-action sample of a thermal control is marked: M.I.P.CO.AKRON.O. (/) PAT.PEND. The smaller copper single-action sample is marked on one side: M.I.P.CO. (/) AKRON O. (/) SUICOL. On the other side, it is marked: 40 H.P. (/) 15 V.A.C.
According to the magazines Popular Science and Professional Engineer, the Multi Slide Rule sold (without company logos) for $1.00. The company distributed its products from Chicago. Mighty Mite Controls began to manufacture bimetal thermostats for appliances in 1946. Thermtrol Corporation of North Canton, Ohio, purchased Mighty Mite in 1996. The patent mentioned on the slide rule may refer to Norman F. Dewar's 1946 application, which was assigned to the Graphic Calculator Company of Chicago (see 2000.3029.13). The patent for the thermal control is not known.
References: Advertisement, Multi-Slide Instrument Corp., Popular Science 147, no. 3 (October 1945): 294; Professional Engineer (1948): 64; Mechanical Industries Production Company, "Mighty Mite" (U.S. Trademark 71,617,720 issued March 24, 1953); Norman F. Dewar, "Slide Rule" (U.S. Patent 2,530,047 issued November 14, 1950).
Location
Currently not on view
date made
after 1945
maker
Multi-Slide Instrument Corp.
ID Number
1995.3051.01
nonaccession number
1995.3051
catalog number
1995.3051.01

Concise 270 Circular Slide Rule

This pocket-sized white plastic duplex circular slide rule has a clear plastic indicator that folds over the edge to serve both sides. It is held together with a metal pivot.
Description
This pocket-sized white plastic duplex circular slide rule has a clear plastic indicator that folds over the edge to serve both sides. It is held together with a metal pivot. The front base has L and D scales, with C, CI, A, and K scales on a sliding disc that fits inside the base. The center of the rotating disc is marked: CIRCULAR CONCISE SLIDE RULE (/) NO. 270 (/) MADE IN JAPAN. Near the center of both sides of the rule, the donor has scratched: SACK. The back base has DI and D scales, with S, T1, T2, and ST scales on the inset sliding disc.
The instrument was received with a clear plastic sleeve, a black vinyl case, and an undated instruction manual. The sleeve is marked: Concise (/) No. 270. As of 2012, Concise continues to manufacture plastic circular slide rules, including models 28N and 270N. The company operated under the name Concise Co., Ltd., which appears on the instruction manual, from 1959 to 1966. The donor, Michael Sackheim, reported that he purchased this rule for calculating during his school days but got little use out of it.
For other slide rules by Concise, see 1985.0636.02, 2003.0012.01, and 2006.0173.01.
References: "Concise Circular Slide Rule," http://www.concise.co.jp/eng0731/circle02.html#02; accession file.
Location
Currently not on view
date made
1959-1966
maker
Concise
ID Number
1996.0141.01
catalog number
1996.0141.01
accession number
1996.0141

Edmund Vernon Slide Rule and Tie Clasp

This small, one-sided sterling silver slide rule is in the form of a tie clip. It has A and D scales on the base and a C scale on the slide. A clear plastic indicator has a red line and is in a metal frame. The back of the clasp is marked: VERNON.
Description
This small, one-sided sterling silver slide rule is in the form of a tie clip. It has A and D scales on the base and a C scale on the slide. A clear plastic indicator has a red line and is in a metal frame. The back of the clasp is marked: VERNON. It is also marked: STERLING.
The donor recalled that he obtained this tie clasp from Edmund Scientific Company. The 1965 catalog of the company lists a tie clasp with a "silver oxide" finish that cost $2.00. The 1971 catalog lists a tie clasp with a gold finish that cost $3.00. However, these tie clips had screws in each corner, while this example has no screws.
References: Edmund Scientific Company, Catalog 661 (Barrington, N.J., 1965), 44; Edmund Scientific Company, Catalog 721 (Barrington, N.J., 1971), 59; Dieter von Jezierski, "Slide Rule Tie Bars," Journal of the Oughtred Society 16, no. 1 (2007): 33–35.
Location
Currently not on view
date made
ca 1965
date received
1996
distributor
Edmund Scientific Company
ID Number
1996.0221.01
catalog number
1996.0221.01
accession number
1996.0221

Perrygraf Clipper Cargo Dimensional Weight Computer Circular Slide Chart

This instrument consists of concentric turquoise and white paper discs and a paper indicator held together with a metal rivet. Around the edge of the turquoise disc is a logarithmic scale of weight in pounds that ranges from 2 to 1,000.
Description
This instrument consists of concentric turquoise and white paper discs and a paper indicator held together with a metal rivet. Around the edge of the turquoise disc is a logarithmic scale of weight in pounds that ranges from 2 to 1,000. Inside this is a scale of lengths from 10" to 50". The white disc has a scale of heights from 5" to 50" and a scale of widths from 6" to 50". The indicator has a scale in densities in cubic inches per pound from 100 to 300 and instructions for setting the dimensions and density of a parcel in order to read off the parcel's weight.
The indicator is marked: PAN AMERICAN WORLD (/) AIRWAYS (/) 506 West Sixth Street (/) Los Angeles 14, California (/) Phone: Michigan 2121 (/) CLIPPER CARGO (/) Dimensional (/) WEIGHT COMPUTER. The white disc is marked: Clipper, Trade Mark, Reg. U. S. Pat. Off. Printed in U.S.A. (/) Copyright 1951, Pan American World Airways, Inc. (/) Slide-Chart by PERRYGRAF, Maywood, Ill. The back of the instrument has a Pan Am compass rose logo at the center of advertising text: ANY WAY YOU MEASURE (/) MAKE CLIPPER CARGO YOUR RULE (/) For All Your Export Shipping (/) See Us For A Free Cost Analysis of (/) CLIPPER CARGO SERVICE (/) via PAN AMERICAN WORLD AIRWAYS.
A slide chart is a slide rule that performs a specific calculation, usually commissioned by a company as a promotional item. In 1934, machinery inspector Lester E. Perry (1901–1991) came up with the idea of equipping salespeople with slide charts so that they could immediately answer customers' questions. Perrygraf Corporation, the company he established in the Chicago, Ill., suburbs, quickly became a dominant force in this market. Pan Am was the principal international air carrier in the United States for most of the 20th century. See also 1996.3029.02, whose copyright date suggests that the latest date this chart was made was 1957.
References: George Melloan, "Pocket Slide Charts Aid Engineers, Help Sell Steel, Lipstick," Wall Street Journal, September 4, 1953, 1; "People: Perrygraf," Waywiser, Harvard University Department of the History of Science website.
Location
Currently not on view
date made
1951-1957
maker
Perry Graf Corporation
ID Number
1996.3029.01
nonaccession number
1996.3029
catalog number
1996.3029.01

Perrygraf Clipper Cargo Dimensional Weight Computer Circular Slide Chart

This instrument consists of two pieces of blue and white rectangular cardboard, riveted together at the corners. It is marked with a circular logarithmic scale of weight in pounds that ranges from 1 to 250. Inside this is a scale of lengths from 50" to 10".
Description
This instrument consists of two pieces of blue and white rectangular cardboard, riveted together at the corners. It is marked with a circular logarithmic scale of weight in pounds that ranges from 1 to 250. Inside this is a scale of lengths from 50" to 10". A white disc attached below that scale has a scale of heights from 5" to 30" and a scale of widths from 30" to 6". A paper indicator is attached on top of the disc. It contains a scale of densities in cubic inches per pound from 300 to 200 and three steps of instructions. This slide chart is marked: CLIPPER CARGO (/) DIMENSIONAL WEIGHT COMPUTER. It performs the same function as 1996.3029.01.
Unlike the other object, a rectangular piece of white cardboard slides inside the instrument to also permit readings of conversions from kilograms to pounds on the front and readings of pounds to kilograms on the back. This part of the chart is marked: WEIGHT CONVERTER. The bottom of the chart is marked: PAN AMERICAN, with LEADERS IN AIR CARGO on the front and SPACE CAN BE RESERVED on the back. The back also has an advertisement: CLIPPER CARGO (/) Reduces Pilferage (/) Reduces Damage (/) Reduces Inventory (/) Extends your working capital!
The lower left corner of the front is marked: Slide-Chart Copr. 1957, (/) PERRYGRAF Corp., Maywood, Ill. The lower right corner is marked: *T.M. Reg. U. S. Pat. Off. Perrygraf was a very successful producer of promotional slide charts. In 1968, the company was sold to Nashua Corporation and moved to Los Angeles, Calif.
Reference: Walter Shawlee II, "The Wonderful World of Slide Charts, Wheel Charts, and Perrygrafs," Sphere Research Corp., http://sphere.bc.ca/test/perrygraf.html.
Location
Currently not on view
date made
1957-1968
maker
Perry Graf Corporation
ID Number
1996.3029.02
nonaccession number
1996.3029
catalog number
1996.3029.02

Ross Precision Computer Circular Slide Rule

This circular slide rule consists of a silver-colored metal dial, 8-1/2" wide, mounted on a silver-colored metal disc. Three oblong holes on the base disc permit the reading of trigonometric scales on a white celluloid and cardboard disc that is between the metal discs.
Description
This circular slide rule consists of a silver-colored metal dial, 8-1/2" wide, mounted on a silver-colored metal disc. Three oblong holes on the base disc permit the reading of trigonometric scales on a white celluloid and cardboard disc that is between the metal discs. The celluloid disc is marked: COPYRIGHTED (/) L. ROSS, SAN FRANCISCO (/) PATENTS PENDING.
On the front of the instrument, the top dial is divided along the outer edge into 400 equal parts. In each quadrant of the dial, the scale is marked from 100 to 1,000, with every tenth division marked. Inside of this scale, there is a spiral scale with 25 coils divided logarithmically from 0 to 1,000, making the rule equivalent to a linear slide rule about 50 feet long. These scales are marked in purple and are worn away in several places, including around much of the edge and underneath where the indicators rest.
Affixed to the center of the disc is a brown metal linear rule, 1-1/8" wide, marked with N, M (Sum), D (Difference), and Root scales. This rule is made of three pieces, but the center no longer slides. Also affixed to the center is a yellow celluloid hairline indicator, 3/4" wide, and a second yellow celluloid indicator, 1-1/2" wide. This indicator is marked on the left side by fours from 0 to 100, labeled Quadrants, and on the right side at varying intervals from 100 to 1,000, labeled Nos. It is attached to a metal handle lined with yellow-white celluloid. The handle is also attached to a pivot at the center back of the instrument. The handle is marked: THE ROSS (/) PRECISION COMPUTER (/) Computer Mfg. Co. (/) San Francisco. The handle has reminders for setting the device for multiplication, division, and proportion, and there is a thumbscrew for making adjustments.
The instrument also came with a loose, wedge-shaped piece of yellow celluloid with a hole at one end for attaching to the center of the computer. It is marked with the names of various trigonometric functions and various angles. The round part of the instrument fits into a black leather case with two snaps, stamped both inside and outside: x THE ROSS ÷ (/) PRECISION COMPUTER (/) COMPUTER MFG. CO. (/) SAN FRANCISCO U.S.A. (/) PAT. PEND. COPYRIGHTED. An instruction manual (1996.3077.02) and a letter and advertising literature (1966.3077.03) sent to the purchaser, Roy Kegerreis of New York, were received with this instrument. The letter is dated July 31, 1918, and the manual was copyrighted in 1919.
Louis Ross of San Francisco designed three circular slide rules in the 1910s: the Precision Computer, the Meridi-o-graph, and the Rapid Computer. Advertisements and reports of surviving instruments indicate that the Precision Computer varied in appearance and size.
The Computer Manufacturing Company sold the Precision Computer for $20.00. A clamp for mounting the rule above a desk sold separately for $2.50. The company claimed its customers included the Panama Canal Commission, DuPont Powder Works, and General Electric. The company's offices were originally located on 25 California Street in San Francisco; in 1921, the factory moved from 268 Market to 340 Sansome. The Sansome address is handwritten inside the instruction manual, suggesting Kegerreis learned about the computer in 1918 but did not purchase one until 1921.
Dr. Roy Kegerreis (1886–1968) obtained his BS in Electrical Engineering from The Ohio State University in 1907, his MS in Mathematics from Harvard, and his PhD in Physics from the University of Michigan in 1917. At the time he purchased this slide rule, he apparently was living in New York City. Kegerreis went on to get an MD in 1934, and he worked for many years as a radiologist. This slide rule was given to the Smithsonian by his daughter, in his memory.
References: Accession file; Edwin J. Chamberlain, "Long-Scale Slide Rules," Journal of the Oughtred Society 8, no. 1 (1999): 24–34, "Long-Scale Slide Rules Revisited," 13, no. 1 (2004): 23–43, and "Circular Slide Rules with Very Long Scales," 17, no. 1 (2008): 52; "A Five-Place Calculating Device," Electrical World 66, no. 11 (1915): 604; "San Francisco Companies Move to New Quarters," San Francisco Business 3, no. 19 (November 11, 1921): 22; "Ross Precision Computer," NIST Museum Digital Archives, http://nistdigitalarchives.contentdm.oclc.org/cdm/ref/collection/p15421coll3/id/266.
Location
Currently not on view
date made
ca 1921
maker
Computer Manufacturing Company
ID Number
1996.3077.01
nonaccession number
1996.3077
catalog number
1996.3077.01

Ross Precision Computer Instruction Manual

This deteriorating 16-page booklet was received with 1996.3077.01. It was copyrighted in 1919, but the address "340 Sansome St." is handwritten on page 3.
Description
This deteriorating 16-page booklet was received with 1996.3077.01. It was copyrighted in 1919, but the address "340 Sansome St." is handwritten on page 3. Since the Computer Manufacturing Company of San Francisco did not move to this location until 1921, the instrument and manual were probably sent out in 1921 or later.
The manual contains general instructions, instructions for using the dial alone, instructions for separately using the linear slide rule attached to the instrument, hints for speed and accuracy, fundamental examples, technical details for calculating with logarithms and exponents, and practical applications from payroll to cube roots. Stamped on pages 8–9 is the text: ANOTHER HINT FOR SPEED (/) In locating answer coil, when a (/) check is desired, set slide ROUGHLY. Pages 9–16 are accessed by folding out the pages from the binding.
Location
Currently not on view
date made
1919
maker
Computer Manufacturing Company
ID Number
1996.3077.02
nonaccession number
1996.3077
catalog number
1996.3077.02

Ross Precision Computer Related Documentation

Two copies of an advertising flyer for the Ross Precision Computer, the Ross Meridi-o-graph, and the Ross Rapid Computer were received with 1996.3077.01. The flyer provides photographs and descriptions of the three instruments.
Description
Two copies of an advertising flyer for the Ross Precision Computer, the Ross Meridi-o-graph, and the Ross Rapid Computer were received with 1996.3077.01. The flyer provides photographs and descriptions of the three instruments. It also cites press releases published in Scientific American 114, no. 3, January 15, 1916, and Engineering News 75, no. 21, May 25, 1916.
Also received was a short letter initialed by the inventor of these devices, Louis Ross, and addressed to Roy Kegerreis of New York City. The letter, dated July 31, 1918, notes the availability of the instruments and offers them on a trial basis. Enclosed were a 3-1/4" by 6-1/2" printed note addressed "To Men in the Army and Navy," describing the suitability of the instruments for military purposes. A second printed note, of the same size, announced the addition of trigonometric scales to the Precision Computer even though the price remained at $20.00.
Location
Currently not on view
date made
1918-07-31
maker
Computer Manufacturing Company
ID Number
1996.3077.03
nonaccession number
1996.3077
catalog number
1996.3077.03

Datalizer Energy Operating Cost Calculator for TVA

This rectangular white cardboard rule has four slides and is held together with ten metal rivets. The top two slides are used to calculate the annual operating cost of a natural gas furnace, while the bottom two slides perform the same calculation for an electric heat pump.
Description
This rectangular white cardboard rule has four slides and is held together with ten metal rivets. The top two slides are used to calculate the annual operating cost of a natural gas furnace, while the bottom two slides perform the same calculation for an electric heat pump. Tables on the back of the instrument give values for building heat loss, typical heating system efficiencies, and heating load hours for the states covered by the Tennessee Valley Authority: Alabama, Georgia, Kentucky, Mississippi, North Carolina, and Tennessee. A sample calculation is also provided on the back.
The front and back are both marked: Electricity (/) THE POWER (/) OF CHOICE. Both sides are also marked: TVA. The rule thus advertised TVA's ability to supply inexpensive public electric power and promote energy conservation. The back bottom left corner is marked: © 1990 Datalizer Slide Charts, Inc., Addison, IL 60101. A former employee of the Perrygraf (or Perry Graf) Corporation (see 1979.3074.03) established Datalizer around 1960, and the company remained in business as of 2012.
References: "From the New Deal to a New Century," Tennessee Valley Authority, http://www.tva.com/abouttva/history.htm; "Slide Chart Specialists," Datalizer Slide Charts, http://www.datalizer.com/about-us/.
Location
Currently not on view
date made
1990
maker
Datalizer Slide Charts, Incorporated
ID Number
1996.3078.02
nonaccession number
1996.3078
catalog number
1996.3078.02

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