US Signal Service Heliograph Photo, 1917

I scanned this image from a magazine page in my collection.

 

It was used to illustrate the article: "Protecting Our Timber Resources: Using the Heliograph to Fight Forest Firest", by Arthur L. Dahl, Scientific American Supplement No. 2168, July 21, 1917. You may read the article on Google Books here.

 

There is also a nice account by a former Forest Service ranger E. Clayton MacCarty of his experiences with the heliograph in 1917 with both the US Signal Service two-tripod heliograph (above) and the single-tripod US Forest Service model here: THE FOREST SERVICE HELIOGRAPH. MacCarty mentions that the US Forest Service used a simplified flash code, rather than Morse, which is discussed

: here.

 

This device is a US Signal Service heliograph, a device for signalling by flashes of mirror-reflected sunlight using Morse or Myer code for ranges up to 45 miles or more. For a summary of the history of the American heliograph, including other images, and hyperlinks to references, see History of the American Heliograph

 

A 1910 US SIgnal Corps manual with a chapter on the heliograph is available for free download in many ebook formats here: Manual No. 6 Visual Signaling

 

My understanding is that, as a work published prior to January 1, 1923 , it is in the public domain in the USA. If the law considers my actions to have given me copyright, I hereby release that copyright to the public domain, as per the Flickr CC0 copyright marking. You are free to do with it as your laws allow (though it is your responsibility to determine what your laws allow).

 

If you wish to reuse this image, you may want to start with one of the larger versions here.

 

 

Done