signalcorps

Photograph in NARA catalogue 111-SC-47661. Taken April 26, 1919. "Wounded soldiers at debarkation hospital No. 3, New York City, New York. Man being fed in bed." U.S. Army Debarkation Hospital No. 3 opened August 2, 1918, in New York City. It comprised four properties: The Greenhut Building, on Sixth Avenue, extending from Eighteenth to Nineteenth Streets; the Cluett Building, 19-23 West Eighteenth Street, and 22-28 West Nineteenth Street, adjoining the Greenhut Building; a building occupying 30-32 West Nineteenth Street, adjoining the Cluett Building; and the Trowmart Inn, Twelfth and Hudson Streets. NARA Source: (catalog.archives.gov/id/86701438)

Another from the May 1908 public field day at Governors Island. The PFC in front has the daytime signal flags. Behind him (and ready for "night work") is a Colt Acetylene Flash Lantern. The acetylene generator and carbide cannister is not yet connected. The signal flags are NOT semaphore flags (the poles are too long). They are used to send morse code. A long sweep overhead was a dash, a short sweep to one side was a dot.

4 of the 6 soldiers are in Signal Corps Uniform. The 2 on the right are in the uniform of the Coastal Artillery - the one in front showing the insignia of a second class gunner.

The tall sergeant in the rear wears the cap insignia and chevrons of a Master Signal Electrician. That flasher is NOT going to malfunction in front of all the VIPs.

No heliograph here, despite the "Tag". As Seuss. says, the displayed device is a signal lantern, specifically a Colt Acetylene Flash lantern, used primarily at night (hence the title at the top of the photograph: "Night Work".). The heliograph used mirrors to reflect sunlight, and were used during the day - there IS a heliograph on display in the accompanying photograph "Day Work", which can be viewed at the Library of Congress, here: www.loc.gov/item/2014680520/ This signal lantern ("Field Lantern" is depicted in Fig. 18 (page 111) of: Manual No. 6, Manual of Visual Signaling of the U.S. Signal Corps, by Captain D. J. Carr, Washington CPO 1905. The heliograph is depicted in Figures 8 & 9 (pp. 76 & 77) of that same manual. There was a Colt Acetylene Flash Lantern on display at the museum at Fort Huachuca, AZ, when I was there last. The 1905 manual gives the brightness of the field lantern as 1,900 candlepower (p. 112), vs. the millions of candlepower from the mirror-reflected sunlight of a heliograph.

Seuss. Here's a photo of a Colt Acetylene Flash Lantern on display at the Fort Gordon Museum. If you click on the thumbnail image below, then scroll down below the photo to the comments, you'll find links to more information about this device. Much of the material is in this thread:
www.treasurebunker.com/forums/index.php?/topic/3804-us-si...

According to Wikipedia: "Major General Robert Alexander (October 17, 1863 – August 25, 1941) was a senior United States Army officer. He served in World War I, where he commanded the 77th Infantry Division on the Western Front." He was notable among U.S. Army officers in that he had originally been an enlisted man and was commissioned from the ranks. One assumes that the band itself is in the nearer foreground and is not visible in the picture.

"39643. The Seventy-seventh Division concert band troupe, band, orchestra, and players, entertaining Maj. Gen. R. Alexander and Col. J.R.R. Hannay in ancient ruins of Chateau Fere. ( Seventy-seventh Division composed of men from metropolitan portion of New York, trained at Camp Upton, Yaphank, N.Y.). Chateau Fere, near Fere en Tardenois, Aisne, France. August 27, 1918. " Catalogue of official A.E.F. photographs by United States. War Dept. General Staff; United States Army. Signal Corps Publication date 1919

looks like it's a hotel and spa now: www.chateaudefere.com/en/

John Robert Rigby Hannay, 1875-1938 His grave at Arlington: www.findagrave.com/cgi-bin/fg.cgi?page=gr&GSln=hannay...; and prabook.com/web/person-view.html?profileId=933837

en.wikipedia.org/wiki/Robert_Alexander_(United_States_Army_officer)