Measuring & Mapping - Overview
Where, how far, and how much? People have invented an astonishing array of devices to answer seemingly simple questions like these. Measuring and mapping objects in the Museum's collections include the instruments of the famous—Thomas Jefferson's thermometer and a pocket compass used by Meriwether Lewis and William Clark on their expedition across the American West. A timing device was part of the pioneering motion studies of Eadweard Muybridge in the late 1800s. Time measurement is represented in clocks from simple sundials to precise chronometers for mapping, surveying, and finding longitude. Everyday objects tell part of the story, too, from tape measures and electrical meters to more than 300 scales to measure food and drink. Maps of many kinds fill out the collections, from railroad surveys to star charts.
"Measuring & Mapping - Overview" showing 411 items.
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Condy Octant
- Description
- An octant measures angles by bringing two images together—that of the sun, for instance, and the horizon—and was used primarily to determine latitude at sea. The form was described by John Hadley in London in 1731 and still in use in the early twentieth century.
- This example is marked "B. CONDY PHILADELPHIA 1778," the signature being that of Benjamin Condy (d. 1798). It was made during the American Revolution, and there are faint markings on the scale that may read "equality" and "justice." It has a mahogany frame and index arm, and ivory inset. The boxwood scale is graduated every 20 minutes from -5° to +95° and read by ivory vernier to single minutes of arc. There is also a back sight and a back horizon mirror for measuring angles greater than 90°. The radius is 17.75 inches.
- Location
- Currently not on view
- Date made
- 1778
- business owner
- Condy, Benjamin
- maker
- Condy, Benjamin
- ID Number
- 1992.0312.01
- catalog number
- 1992.0312.01
- accession number
- 1992.0312
- catalog number
- 92.312.1
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Astronomical Spectroscope
- Description
- This is a spectroscope, designed to be used with a telescope to study the light of the sun. It was made in Dublin in 1877 by the famous instrument maker Howard Grubb (1844–1931). It was used with the 9 ½ inch Alvan Clark & Sons refractor in the Observatory of Princeton University.
- When the College of New Jersey at Princeton hired the astronomer Charles A. Young in 1877, they also gave him funds to equip the new John C. Green student observatory. One of his first purchases was this instrument. It was custom-made, and Young helped refine the design. (Grubb's company later advertised that this was the first such spectroscope that they had sold.) The most unusual feature of this instrument is the use of a complicated system of multiple prisms to disperse the light and produce a highly detailed view of the solar spectrum.
- In use, the spectroscope was mounted at the eyepiece end of the telescope and light from the sun would be directed through it. As the light passed from one prism into the next, it would be increasing dispersed, or spread out. To make the instrument more compact, the beam of light was directed first through the upper portion of the prisms and then back through the bottom part. Depending on how it was configured, the light could thus be passed through either 2, 4, 6 or 8 prisms. A particular area of the solar spectrum could be viewed by turning a small chain that moved each prism by the same amount. Because of the large number of optical surfaces involved, the light loss in this instrument was almost certainly in the 90 percent range. This was an advantage when viewing the Sun, but it reduced the usefulness of this instrument for other purposes, such as measuring the spectra of stars. The success of this instrument in making precise measurements of the solar spectrum (and thus revealing information about the composition of the sun and its atmosphere) led to its wider adoption as an important astronomical tool.
- Date made
- 1877
- user
- Young, Charles A.
- maker
- Grubb, Howard
- ID Number
- PH*328885
- accession number
- 277637
- catalog number
- 328885
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Hagger Theodolite
- Description
- This theodolite belonged to Smith College, but was made well before that school was established. The "Hagger Maker Baltimore" signature refers to Benjamin K. Hagger, an instrument maker who worked in Baltimore during the period 1816–1824, and who later went into partnership with his eldest son. The horizontal circle and vertical arc are silvered, graduated every 30 minutes, and read by verniers to single minutes.
- maker
- Hagger, Benjamin K.
- ID Number
- 1980.0098.03
- accession number
- 1980.0098
- catalog number
- 1980.0098.03
- Data Source
- National Museum of American History, Kenneth E. Behring Center
B. Pike & Son Transit
- Description
- The "B. Pike & Son. New York. Warranted" signature identifies the shop in which this instrument was sold, but not necessarily where it was made, or by whom. It was used between 1831 and 1841, when Benjamin Pike worked with his son Benjamin Jr., and again between 1843 and 1850, when Benjamin Pike worked with his son Daniel. The word "Warranted" represents the Pikes' guarantee of quality. In design and production, however, this instrument is less successful than those made by men who specialized in instruments of this sort.
- As in William J. Young's original surveyor's transit, the horizontal circle here is inside the compass face. The circle, however, is graduated every 30 minutes of arc, and read by vernier to single seconds. The vertical circle is graduated every 1 degree, and read by vernier to 4 minutes.
- maker
- B. Pike & Son
- ID Number
- 1980.0254.01
- accession number
- 1980.0254
- catalog number
- 1980.0254.01
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Queen & Company Wye Level
- Description
- This is marked "QUEEN & CO. PHILADA 6750." The firm termed it an Improved Engineer's Y Level, and priced it at $110. The serial number suggests a date from the mid-1890s. A label in the box reads "QUEEN & CO., Inc.," referring to the incorporation of the firm in 1896.
- Ref: Queen & Co., Catalogue of Mathematical and Engineering Instruments and Materials (Philadelphia, 1887), pp. 153-154.
- maker
- Queen and Company
- ID Number
- 1980.0319.01
- accession number
- 1980.0319
- catalog number
- 1980.0319.01
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Chandlee Surveyor's Compass
- Description
- This compass bears two distinct inscriptions: "G*CHANDLEE W." refers to the maker, and "J:J: WELSH" refers to the owner (who has yet to be identified). Goldsmith Chandlee (1751-1821) was born in Nottingham, Md., and apprenticed with his father Benjamin Chandlee, himself a notable clock and instrument maker. Goldsmith moved to Stephensburg, Va., in 1775. The W on this compass refers to Winchester, Va., where Chandlee settled in 1783.
- Some 22 Goldsmith Chandlee compasses are known today, and almost all have an L/T table. In this example, the table appears on the south arm. This L/T table converts links of a chain to tenths of perches, and vice versa, thus helping the surveyor determine the length of the line that had been run. A perch, in England and the United States, was equal to 16.5 feet.
- All Goldsmith Chandlee compasses have an outkeeper (an attachment to keep a tally in chaining). In this example, the outkeeper appears at the south end of the face. Most Goldsmith Chandlee compasses were made to order, and the name of the original owner is engraved on the face.
- Ref: Edward E. Chandlee, ed., Six Quaker Clockmakers (Philadelphia, 1943), pp. 105-146.
- Richard Elgin, "On Goldsmith Chandlee," Professional Surveyor 21 (December 2001): 16-26.
- maker
- Chandlee, Goldsmith
- ID Number
- 1980.0809.01
- accession number
- 1980.0809
- catalog number
- 1980.0809.01
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Hanks Surveyor's Compass
- Description
- Benjamin Hanks (1755-1824) apprenticed with Thomas Harland, an English clock maker who had recently migrated to Norwich, Conn. By 1777 Hanks was in business on his own in Windham, Conn. Like many American mechanics of that time, Hanks applied his skills in several directions. While specializing in clocks and watches, for instance, he asked the General Assembly to supply funds so that he could construct looms for weaving stockings. Hanks moved to Litchfield in 1780, and advertised surveyor's compasses in 1785. In 1786 he began casting bells. In 1808, now living in Mansfield and working in partnership with his son Julius, Hanks was making vernier compasses or, as he advertised, “surveyor's compasses upon the Rittenhouse improved plan.”
- This compass was probably made early in Hanks's career. The face reads clockwise, and the bar is narrow. The north metal brace bears the inscription “HANKS.” One unusual feature is the clinometer scale at the south end of the face, which could be used to measure vertical angles; the clinometer needle is missing.
- Ref: Penrose R. Hoopes, Connecticut Clockmakers of the Eighteenth Century (Hartford, 1930), pp. 79-83.
- Charles E. Smart, American Surveying Instruments and Their Makers (Troy, 1962), pp. 70-71.
- maker
- Hanks, Benjamin
- ID Number
- 1981.0182.01
- accession number
- 1981.0182
- catalog number
- 1981.0182.01
- Data Source
- National Museum of American History, Kenneth E. Behring Center
"American Method in Astronomical Observation"
- Description
- From its infancy, timekeeping has depended on astronomy. The motion of celestial bodies relative to the rotating Earth provided the most precise measure of time until the mid-twentieth century, when quartz and atomic clocks proved more constant. Until that time, mechanical observatory clocks were set and continuously corrected to agree with astronomical observations.
- The application of electricity to observatory timepieces in the late 1840s revolutionized the way American astronomers noted the exact movement of celestial events. U.S. Coast Survey teams devised a method to telegraph clock beats, both within an observatory and over long distances, and to record both the beats and the moment of observation simultaneously. British astronomers dubbed it the "American method of astronomical observation" and promptly adopted it themselves.
- Transmitting clock beats by telegraph not only provided astronomers with a means of recording the exact moment of astronomical observations but also gave surveyors a means of determining longitude. Because the Earth rotates on its axis every twenty-four hours, longitude and time are equivalent (fifteen degrees of longitude equals one hour).
- In 1849 William Cranch Bond, then director of the Harvard College Observatory, devised an important improvement for clocks employed in the "American method." He constructed several versions of break-circuit devices—electrical contracts and insulators attached to the mechanical clock movement—for telegraphing clock beats once a second. The Bond regulator shown here incorporates such a device. Bond's son Richard designed the accompanying drum chronograph, an instrument that touched a pen to a paper-wrapped cylinder to record both the beats of the clock and the instant of a celestial event, signaled when an observer pressed a telegraph key.
- Location
- Currently not on view
- Date made
- ca 1850
- maker
- William Bond & Son
- ID Number
- 1981.0322.01
- accession number
- 1981.0322
- catalog number
- 1981.0322.01
- Data Source
- National Museum of American History, Kenneth E. Behring Center
W. J. Young Surveyor's Vernier Compass
- Description
- This compass is marked "Wm. J. Young Maker Philadelphia." It is not dated, but we know that William J. Young began using this particular signature around 1840, and he began putting serial numbers on his instruments in the early 1850s. The variation arc on the north arm extends 27 degrees either way. The vernier is moved by rack and pinion located on the south arm and hidden under a brass plate, and reads to 5 minutes. A circular level vial is on the south arm and an outkeeper on the north arm. The face is dark, and the needle ring was probably silvered originally.
- Ref.: D. J. Warner, "William J. Young. From Craft to Industry in a Skilled Trade," Pennsylvania History 52 (1985): 53-68.
- maker
- Young, William J.
- ID Number
- 1981.0648.02
- accession number
- 1981.0648
- catalog number
- 1981.0648.02
- Data Source
- National Museum of American History, Kenneth E. Behring Center
Bowles Surveyor's Compass
- Description
- This is a wooden compass with a paper card, the central circle of which is marked, “T. S. BOWLES*PORTSMOUTH, N. H.*” The signature refers to Thomas Salter Bowles, who was baptized in Portsmouth, N.H., in 1785. An advertisement in the Portsmouth Oracle for May 31, 1806, notes that Bowles was a mathematical instrument maker who had just taken a shop in Daniel Street, and that his wares included “Azimuth and brass Compasses, wood and Hanging Compasses.” Bowles was still in business in 1821. Several Bowles compasses with different cards are known. Unlike most wooden compasses, this one has a brass band around the outside of the box, and a brass needle ring graduated to 1 degree of arc.
- Ref: Silvio A. Bedini, Early American Scientific Instruments and Their Makers (Washington, D.C., 1964), pp. 124-126.
- maker
- Bowles, Thomas Salter
- ID Number
- 1981.0708.01
- catalog number
- 1981.0708.01
- accession number
- 1987.0706
- Data Source
- National Museum of American History, Kenneth E. Behring Center
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