The Library of Congress

  • 44,872 photos
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  • Member since 2008
  • Last upload was
    23 January
  • 🇺🇸
Yes. We really are THE Library of Congress. We invited your tags and comments and you responded. Wow, did you respond! Thank You. The identifying information is appreciated--many of our old photos came to us with very little description.

When were these photos taken?

10578
1825
2023

 

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<1% of these photos are geotagged.

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The last upload was 23 January.

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Quincy Service Station, Quincy, Massachusetts (LOC)

from The Library of Congress

Hat & Boots Texaco, Seattle, Washington (LOC)

from The Library of Congress

  • swanq said:
    See
    Hat & Boots Texaco, Seattle, Washington (LOC)

12th Infantry, Signal Corps, Day Work, Governor's Island, N.Y. (LOC)

from The Library of Congress

  • 2 older comments, and then…
  • Seuss. said:
  • signal mirror said:
    The heliograph was used to signal using dots and dashes of reflected sunlight, and was used at ranges up to 20 miles and more. It consists of two tripods at center. The left tripod holds a mirror and a foresight to reflect and aim the light, and the right tripod a shutter to break up the reflected sunlight into dots and dashes. The thumbnail image below is a clickable link to a photo I took of a surviving example of this type of heliograph:
  • signal mirror said:
    Seuss. The diagram you posted is of the 1888 model - some slight changes were made between that and the 1905 model shown here, though the parts and functions were, for the most part, the same. The big change was from the single-flap shutter to the six-blade shutter. Another change was the provision of azimuth adjustment screws on both ends of the mirror bar. The thumbnail below is a hyperlink to a 1913 advertisement for a model 1905 heliograph like the one in the Library of Congress photo:
  • signal mirror said:
    The Library of Congress also holds a movie of a heliograph like that above in use by US Marines in 1915. The movie shows the heliograph being transported, set up, and operated. A copy is on YouTube, here:
    www.youtube.com/watch?v=tdv11gZAUI8

    The thumbnail below is a hyperlink to this still from that movie:
  • signal mirror said:
    A modern video of a heliograph of the type in this LOC photo (operated by a complete beginner) is on YouTube here:
    youtu.be/pBgH0Rz7kXY

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