Antique Scientific Instruments in the US Geological Survey Museum
Posted by Laurie Frost on May 11, 2010
First, a question. Tonight when I opened this site using IE, most of the pictures for my last post didn’t load. They did load on Firefox, however. Is anyone else having trouble?
When I was working on the Lesser Known Volcanoes of the USA post, I thought I’d have a look around the US Geological Survey’s Multimedia Gallery. It took me a little time to figure out how to navigate it. When you get to the Gallery’s homepage, you will find three divisions: Photography, Video, and Audio. For each a recent collection is highlighted. For example, tonight in Photography, Gulf of Mexico Oil Spill – Landsat is featured. Clicking on the image gets you to that collection alone. To see what other images are available, you need to go to Browse by or View all.
Choosing Browse by Collections for Photography, you’ll find 21 collections. The number of pictures in each varies widely, from just 2 in National Parks to 913 in Natural Hazards.
Tonight’s posts are a selection of the 152 photos in the USGS Museum section. I have used the captions provided by the USGS staff as well. Unless otherwise noted, the photographer is listed as USGS Museum Staff. All are public domain, but the USGS asks that a credit line is given: Credit: U.S. Geological Survey, Department of the Interior/USGS, and photographer, if named.
I never knew what a benchmark was until I saw these pictures: read on.
Quintant Sextant or Lattice Sextant
Description: This instrument was manufactured by Spencer, Browning & Rust, London. A sextant is used for measuring the altitude of the sun or another celestial body; such measurements can then be used to determine the observer’s geographical position or for other navigational, surveying, or astronomical applications. Dating from the 1820s-1850s, this instrument is among the earliest objects in the U.S. Geological Survey museum collection. Object ID: USGS-000220
Engineer’s and Surveyor’s Transit
Object ID: USGS-000187 Photographer: Justin Bongard, U.S. Geological Survey
Description: A pocket instrument used in surveying which consists of a fixed sighting tube, a movable spirit level connected to a pointing arm and an arced scale graduated 0 to 90º in both directions. When correctly used, the Abney Level is an accurate surveying tool used to measure degrees, percent of grade and topographic elevation. Object ID: USGS-000334
Mannheim Type Slide Rule with Leather Sleeve
Description: Original Box & Booklets. Marketed as being made of Ivorite, this slide rule was manufactured by Keuffel & Esser Company, New York & New Jersey in the 1960s. All slide rules consist of three parts (the stock, the slide and the cursor or indicator) and have logarithmic scales that can be moved in relation to each other in order to do basic mathematical calculations. Slide rules were largely supplanted by electronic calculators in the 1980s. Object ID: USGS-000653
Description: Manufactured by Q-O-S Corporation, New York for the U.S. Army Corp of Engineers. Although originally designed for military reconnaissance work, this type of instrument was used for map reading of aerial photographs up to 8″. Object ID: USGS-000235
Description: Distilling Apparatus or Still. The prominent feature of this antique lab equipment is the spherical copper globe. Object ID: USGS-000240
Cast Bronze Benchmark
Description: Benchmarks can be divided into two general groups: the “vertical control points” are points that mark a very precise elevation above the standard datum plane (usually referred to as elevation above sea level) and the “horizontal control points” are points with precisely established latitude and longitude. The National Geodetic Survey, not the U.S. Geological Survey, is the Maintainer of federal Vertical Control Marks. This specimen is a Reference Benchmark and not a geodetic control mark. In actual use, this marker would have been used to keep the location of a triangulation station from being lost. Its arrow would be set to the location of the triangulation station; the station’s description would have accurate azimuth and horizontal (not slope) distance to each of its reference marks so that it can be re-set from them if necessary. Object ID: USGS-000181
Pendulum Self-leveling Alidade
Description: This is a telescopic alidade in which a pendulum device, or compensator replaces the conventional bubble for establishing a horizontal reference line from which vertical angles may be measured. Alidades were the primary mapping instrument in the U.S. from about 1865 to the 1980s, when they were replaced by the total station. Object ID: USGS-000160
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