File:ChartersOfFreedom 033.jpg
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| Description | E. C. Creitz of the NBS Gas Chemistry Laboratory installing two of the leak-detecting cells sealed in the channel around the edge of the enclosure. For each enclosure, four cells were involved. Two of these were sealed within the enclosure and two were located in the channel along with the enclosure edge. By plugging the leak detecting meter into the leads of the four cells, a small current energized the cells. The circuit of these cells was so arranged so that the instrument compared the resistance of the four cells, the two measuring cells with the two outside reference cells. The comparison indicated whether any change had occured in the composition of the gas within the enclosure. If a change had occured, the cells were not in balance and the meter indicated a leak. |
| Source | National Institute of Standards and Technology |
| Author | National Institute of Standards and Technology |
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The images in the ChartersOf Freedom Photographic Collection are in the public domain and are not subject to copyright in the United States. However, please pay special attention to the individual works to make sure there are no copyright restrictions indicated. Individual works may require securing other permissions from the original copyright holder. Use of the images from NIST Digital Collections is not restricted, but a statement of attribution is required. Please use the following attribution statement: "National Institute of Standards and Technology Digital Collections, Gaithersburg, MD 20899." |
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This work is in the public domain in the United States because it is a work prepared by an officer or employee of the United States Government as part of that person’s official duties under the terms of Title 17, Chapter 1, Section 105 of the US Code.
Note: This only applies to original works of the Federal Government and not to the work of any individual U.S. state, territory, commonwealth, county, municipality, or any other subdivision. This template also does not apply to postage stamp designs published by the United States Postal Service since 1978. (See § 313.6(C)(1) of Compendium of U.S. Copyright Office Practices). It also does not apply to certain US coins; see The US Mint Terms of Use.
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| This file has been identified as being free of known restrictions under copyright law, including all related and neighboring rights. | ||
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| current | 16:01, 19 February 2014 | | 5,922 × 4,858 (1.55 MB) | NISTResearchLibrary (talk | contribs) |
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