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Thacher's calculating instrument
Date: circa 1920
Inventory Number: 2016-1-0047
Classification: Slide Rule
Subject:
Maker: Keuffel & Esser Company (1867 - 1987)
Inventor: Edwin Thacher (1839 - 1920)
Cultural Region:
Place of Origin:
City of Use:
Dimensions:
14.5 x 57.5 x 13 cm (5 11/16 x 22 5/8 x 5 1/8 in.)
box: 16.5 x 60.5 x 16.8 cm (6 1/2 x 23 13/16 x 6 5/8 in.)
Accessories: instruction booklet, information sheet; box
DescriptionThis instrument consists of a cylindrical slide provided with a wooden knob at each end. This cylinder can both rotate and move horizontally within an open envelope of equidistant bars of triangular section (twenty in all, numbered 1 to 20). The latter are connected to brass rings at each end, attached to a wooden base.
The bars have two sets of scales (marked "B" and "C"), which are used in conjunction with those (marked "A")on the cylinder.
A triangular brass bar is mounted on the rear of the envelope. It carries a slider with a locking screw. The magnifying glass held in the slider is now missing.
The base has an instruction sheet glued to it. It is titled "THACHER'S / CALCULATING INSTRUMENT. / DIRECTIONS AND RULES FOR / OPERATING."
Near the right front corner of the base is a ivory-colored plate screwed down. It is blank.
When not in use, the instrument is stored in a fitted mahogany box. A trade card is glued on the inside cover of the box.
An instruction manual is included in the instrument case. It is entitled Directions for Using Thacher's Calculating Instrument by Edwin Thacher and published by Keuffel & Esser Co., New York, 1920. The cover is stamped "Property of / Harvard Economic Society, Inc."
A typed page of instructions is folded in the booklet and marked in pencil "Please return to box."
The bars have two sets of scales (marked "B" and "C"), which are used in conjunction with those (marked "A")on the cylinder.
A triangular brass bar is mounted on the rear of the envelope. It carries a slider with a locking screw. The magnifying glass held in the slider is now missing.
The base has an instruction sheet glued to it. It is titled "THACHER'S / CALCULATING INSTRUMENT. / DIRECTIONS AND RULES FOR / OPERATING."
Near the right front corner of the base is a ivory-colored plate screwed down. It is blank.
When not in use, the instrument is stored in a fitted mahogany box. A trade card is glued on the inside cover of the box.
An instruction manual is included in the instrument case. It is entitled Directions for Using Thacher's Calculating Instrument by Edwin Thacher and published by Keuffel & Esser Co., New York, 1920. The cover is stamped "Property of / Harvard Economic Society, Inc."
A typed page of instructions is folded in the booklet and marked in pencil "Please return to box."
Signedon base, stamped circular logo: KEUFFEL & ESSER CO. / N. Y.
on base, stamped: [KE griffon logo]
printed on paper on cylinder: Made by Keuff[el & ]Esser Co., New York.
printed on paper on cylinder: Patented by Edwin Thatcher [sic], C.E. Nov. 1st 1881.
printed on paper on cylinder: Divided by W. F. Stanley, London, 1882.
stamped on celluloid label in box lid: KEUFFEL & ESSER CO. / ST. LOUIS CHICAGO / NEW YORK / U.S.A.
printed paper trade card pasted to box lid: KEUFFEL & ESSER CO., / MANUFACTURERS OF / Mathematical & Surveying Instruments, / 127 Fulton St. & 42 Ann St., / NEW YORK. / BRANCHES: 111 MADISON ST., CHICAGO. / 708 LOCUST ST., ST. LOUIS. / 303 MONTGOMERY ST., SAN FRANCISCO.
printed below images of factories on the trade card: FACTORIES OF KEUFFEL & ESSER CO., HOBOKEN, N. J.
on base, stamped: [KE griffon logo]
printed on paper on cylinder: Made by Keuff[el & ]Esser Co., New York.
printed on paper on cylinder: Patented by Edwin Thatcher [sic], C.E. Nov. 1st 1881.
printed on paper on cylinder: Divided by W. F. Stanley, London, 1882.
stamped on celluloid label in box lid: KEUFFEL & ESSER CO. / ST. LOUIS CHICAGO / NEW YORK / U.S.A.
printed paper trade card pasted to box lid: KEUFFEL & ESSER CO., / MANUFACTURERS OF / Mathematical & Surveying Instruments, / 127 Fulton St. & 42 Ann St., / NEW YORK. / BRANCHES: 111 MADISON ST., CHICAGO. / 708 LOCUST ST., ST. LOUIS. / 303 MONTGOMERY ST., SAN FRANCISCO.
printed below images of factories on the trade card: FACTORIES OF KEUFFEL & ESSER CO., HOBOKEN, N. J.
Inscribedmodel no. stamped on base and on trade card in box lid: 4013
serial no. stamped on base and on trade card in box lid: 1074
serial no. stamped on base and on trade card in box lid: 1074
FunctionExcerpt from the instruction manual:
"By the use of this instrument the drudgery of calculation is avoided, and the relief to the mind may be compared with the most improved mechanical appliances in overcoming the wear and tear of manual labor....
"By use of this instrument results are more reliable than when brought out in the usual way; mistakes are less liable to occur, and if they should occur the whole work can be quickly checked. The only liability to error is in the misreading of the figures and divisions upon the scales, which are essentially the same as the reading of the inches and parts of a carpenter's rule....
"The bridge engineer will find it useful in finding the moments and shears in plate girders, the strains and sections in trusses, the bearing an shearing values of pins and rivets, the thickness of bearing plates, the length of tie plates, and estimates of quantities, costs, etc.
"The railway engineer will find it useful in the mensuration of lines, areas, and solids....
"The mechanical engineer will find it useful ... in finding the pitch, number of teeth, and diameter of toothed wheels....
"The hydraulic engineer will find it useful in ascertaining the force, velocity, and pressure of water....
"The architect and actuary, not less than the engineer, will find it useful in their various calculations and estimates."
"By the use of this instrument the drudgery of calculation is avoided, and the relief to the mind may be compared with the most improved mechanical appliances in overcoming the wear and tear of manual labor....
"By use of this instrument results are more reliable than when brought out in the usual way; mistakes are less liable to occur, and if they should occur the whole work can be quickly checked. The only liability to error is in the misreading of the figures and divisions upon the scales, which are essentially the same as the reading of the inches and parts of a carpenter's rule....
"The bridge engineer will find it useful in finding the moments and shears in plate girders, the strains and sections in trusses, the bearing an shearing values of pins and rivets, the thickness of bearing plates, the length of tie plates, and estimates of quantities, costs, etc.
"The railway engineer will find it useful in the mensuration of lines, areas, and solids....
"The mechanical engineer will find it useful ... in finding the pitch, number of teeth, and diameter of toothed wheels....
"The hydraulic engineer will find it useful in ascertaining the force, velocity, and pressure of water....
"The architect and actuary, not less than the engineer, will find it useful in their various calculations and estimates."
Historical AttributesUsed by the Harvard Economic Society, Inc..
Curatorial RemarksPatented by Thacher in 1881, the original scale divisions are dated from 1882, and were done by the London based W. F. Stanley. Keuffel & Esser Co. took over the production of this slide rule in 1897. It is interesting to note that Stanley misspelled Thacher's name (Thatcher) on the original engraving, and K&E never bothered to correct the mistake in the following decades.
For more information on this type of slide rule, including the above information and the patent's text, take a look at the following website.
For more information on this type of slide rule, including the above information and the patent's text, take a look at the following website.
Primary SourcesEdwin Thacher., Directions for Using Thacher's Calculating Instrument (New York: Keuffel & Esser Co., 1920).