Periscope view of the Russian trenches, February, 1916. The message dated February 24, 1916 notes that the hash marks from the central point are measured in meters.
A short translated part of the writing on the reverse side:'... a picture showing Russian trenches through periscope, the signs + - mean 10 meters ...'Translation courtesy Thomas Faust, Ebay's Urfaust.
"On 24th February [1916]—three days after the Germans launched their attack on Verdun—there was a conference in Stavka. The Russian superiority of numbers was now considerable—on the northern front, 300,000 to 180,000; on the western, 700,000 to 360,000 (917 battalions to 382) with 526 cavalry squadrons to 144; and on the south-western front, about half a million men on either side (684 Russian battalions to 592, and 492 squadrons to 239)."
The Germans launched the Battle of Verdun on February 21, 1916 with a bombardment of over 1,000 guns along the Verdun salient, continuing the attack the next day with artillery and infantry assaults. The French immediately requested a Russian offensive to relieve the pressure. Stavka was the Russian General Headquarters, under the command, since the summer of 1915, of Tsar Nicholas.
The Eastern Front, 1914-1917 by Norman Stone, page 227, copyright © 1975 Norman Stone, publisher: Charles Scribner's Sons, publication date: 1975
1916-02-24, 1916, February, Russian Front, Eastern Front