Heliographing 70 miles in 1895
I photographed this figure from an 1895 magazine in my collection.
It depicts an oversized American heliograph - the usual mirrors were 4.5" square. The "station" mirror variant had 8" mirrors - perhaps this is one of those. The article does mention the fact that the Department of Colorado held the world's record, which was set just one year prior using 8"x8" mirrors to perform two-way Morse Code communication over 183 miles.
The heliograph was used to signal by mirror-reflected sunlight, modulated into the dots and dashes of Morse Code or Myer Code. The American heliograph used a shutter on a second tripod for modulation.
This image is from the article: "Signaling from Long's Peak in Colorado", and appeared on page 167 of Leslie's Weekly Illustrated, Vol LXXXI, No. 2087, September 12, 1895.
Here are some excerpts from the story:
"A twinkling star seventy miles away in the mountains the other day caught the eyes of Denver people. ... A heliograph in the hands of an expert of the United States Army Signal Corps was responsible for the flash that came from the mountains. On the top of the Equitable building in Denver, Captain William A. Glassford, chief signal officer of the Department of the Colorado, and his men received the intelligence. It came in dots and dashes, in the Morse code, and was as easily interpreted as the click of the telegraph. Messages were sent from Denver to the party on Long's Peak, and when "30" was flashed, the operators folded their instruments and started for a toilsome climb to the summit of Gray's Peak, where the next experiments were to be made.
...
The heliographing outfit consists of a mirror, a "shutter," a telescope and a field-glass. The mirror and "shutter" are each mounted on tripods for convenience. When it is desired to communicate with a party in any specified locality the mirror is set so as to throw a reflection on the spot where the answering party is supposed to be located. By sweeping the horizon the answering flash indicates when the mirror is correctly set. The opening and closing of the shutter in front of the mirror gives the effect of dots and dashes and enables the second party to receive the message. At ordinary distances the telescope is not found necessary.
The world's record in long-distance signaling is held by the Department of the Colorado. ...."
I make no copyright claim to this - you are free to use it as your laws allow. As an image published prior to January 1, 1923, it should be in the public domain in the USA, but rights determination is your responsibility. In the event that it turns out that my action entitles me to copyright, I release it to the public domain, as indicated by the Flickr CC0 copyright marking.
You can view/download other sizes of this image here.
Heliographing 70 miles in 1895
I photographed this figure from an 1895 magazine in my collection.
It depicts an oversized American heliograph - the usual mirrors were 4.5" square. The "station" mirror variant had 8" mirrors - perhaps this is one of those. The article does mention the fact that the Department of Colorado held the world's record, which was set just one year prior using 8"x8" mirrors to perform two-way Morse Code communication over 183 miles.
The heliograph was used to signal by mirror-reflected sunlight, modulated into the dots and dashes of Morse Code or Myer Code. The American heliograph used a shutter on a second tripod for modulation.
This image is from the article: "Signaling from Long's Peak in Colorado", and appeared on page 167 of Leslie's Weekly Illustrated, Vol LXXXI, No. 2087, September 12, 1895.
Here are some excerpts from the story:
"A twinkling star seventy miles away in the mountains the other day caught the eyes of Denver people. ... A heliograph in the hands of an expert of the United States Army Signal Corps was responsible for the flash that came from the mountains. On the top of the Equitable building in Denver, Captain William A. Glassford, chief signal officer of the Department of the Colorado, and his men received the intelligence. It came in dots and dashes, in the Morse code, and was as easily interpreted as the click of the telegraph. Messages were sent from Denver to the party on Long's Peak, and when "30" was flashed, the operators folded their instruments and started for a toilsome climb to the summit of Gray's Peak, where the next experiments were to be made.
...
The heliographing outfit consists of a mirror, a "shutter," a telescope and a field-glass. The mirror and "shutter" are each mounted on tripods for convenience. When it is desired to communicate with a party in any specified locality the mirror is set so as to throw a reflection on the spot where the answering party is supposed to be located. By sweeping the horizon the answering flash indicates when the mirror is correctly set. The opening and closing of the shutter in front of the mirror gives the effect of dots and dashes and enables the second party to receive the message. At ordinary distances the telescope is not found necessary.
The world's record in long-distance signaling is held by the Department of the Colorado. ...."
I make no copyright claim to this - you are free to use it as your laws allow. As an image published prior to January 1, 1923, it should be in the public domain in the USA, but rights determination is your responsibility. In the event that it turns out that my action entitles me to copyright, I release it to the public domain, as indicated by the Flickr CC0 copyright marking.
You can view/download other sizes of this image here.