As noted, the Russo-Japanese War became the impetus for the use of sound intelligence. Artillery acquired the ability to shoot at long distances, at invisible targets. At the same time, the artillery became invisible to the enemy. It was then that the idea came to mind to use sound for reconnaissance of shooting guns and for firing at them. True, during the Russo-Japanese War, no methods or methods for determining the location of firing guns by sound were developed. However, some officers have already used the principle of difference in the speed of propagation of light and sound. Noticing the brilliance of the shot of the gun behind the closure, the observer determined the time of reaching the sound - and judged the distance from the counted time interval. Later, as a stopwatch-rangefinder, Boulanger proposed the first simplest sound-measuring device based on this principle and allowing to automatically obtain an approximate distance to the gun (Aparin A. A.
The proposal of the Russian officer N. A. Benois in 1909, which made it possible to determine the location of enemy batteries by the sound of a shot, turned out to be more perfect and not dependent on optical observation.
In foreign armies, such proposals appeared only at the beginning of the First World War in 1914-1918. (Esclangon in France, Paris in England). In the already cited work of Barsukov, we can read the following: “Experiments in the use of sound measurement in Russian artillery arose 3 - 4 years before the start of the world war, that is, earlier than anywhere else in foreign artillery. Before the war itself, sound-measuring teams were formed with these devices (sound-measuring) and sent to the theater of war (Barsukov. T. I. S. 95.)
According to participants in the first experiments in the use of sound reconnaissance in the war of 1914-1918, one of these teams went to the front in August 1914. A team of 6 people first tried to turn around on the Lublin front, participating in battles near the villages of Bykovo and Golenzovo - but before the end of the battle she did not have time to turn around. But the second time, in the battles on the Vistula near the town of Kamen (September 1914), the team turned around and spotted three enemy batteries.
Nevertheless, although already at the beginning of the 1914 campaign, sound reconnaissance teams were operating in the Russian army, their work was of an experienced nature until the very end of the war. Sound-metric reconnaissance never left the testing stage, which was partly facilitated by the imperfection of the material part: the sound-measuring stations available in 1916 in the Russian army: 1) VZh (named after the designers - Volodkevich and Zheltov) and 2) the inventor Levin was not satisfactory enough. Note that these two stations already at that time had a graphical record, therefore, they provided documentary, in contrast to the third station, which was in the army, - a chronographic one. The latter (the Benois system station) had an imperfect sound receiver - and the results of its work were ineffective. Unfortunately, almost no information has been preserved about the operation of the first two stations.
Already at the end of 1917, the unsatisfactory organization of the detachments of artillery observation stations (as the sound-measuring detachments were called by that time) and the ineffectiveness of finding them at the fronts became clear - as a result of which they had to go to Tsarskoe Selo, to the spare Heavy Brigade - to reorganize on new grounds.
At the same time, Russian artillerymen widely used (for example, during the 1916 Offensive) the above-mentioned sound-and-light method of determining the range - for the production of artillery fire.
This is, in brief, the history of sound reconnaissance in the Russian army until the end of 1917.
Some information about the use of sound reconnaissance in the French army is found only at the beginning of 1915, and in the German army even later. Abroad, as well as in Russia, at the beginning of the war, the role of this powerful weapon was clearly underestimated.
Here is what Academician Exclangon, who was involved in work on sound measurement in 1915, writes about this: "One general answered me that, in his opinion, this question has no practical significance." And in another case: “In the bureau of the War Ministry, I was received by its chief, who treated the proposal attentively and with courtesy, but also skeptical. The young captains who were present at the event spoke even ironically."
In the German army at the beginning of the war, the opinion also prevailed that only aerial reconnaissance and the predominant study of aerial photographs provide basic information for the use of artillery. By the end of the war, this view had changed radically. So, one officer, a specialist in the German army, noted that in 1918 the use of a division without light and sound reconnaissance was unthinkable. The corresponding means won recognition in foreign armies - and by the end of the war, sound-metric reconnaissance had become one of the main means of reconnaissance of enemy artillery.
As an illustration, we present a number of data characterizing the work of sound-metric reconnaissance at the end of the 1914-1918 war. So, for example, in the 2nd French army for the period from June 22 to August 13, 1918, on the stabilized front, out of 159 main enemy positions were determined: by sound measurement - 45 positions (or 28%); light metering - 54 positions (or 34%); aviation - 60 positions (or 38%).
In the 1st French army for the period from April 7 to August 8, 1918, 974 targets were identified by sound-metric reconnaissance, and 794 targets by light-metric ones. These goals were determined with errors: at a distance of up to 50 meters - for sound metering 59% and light metering 34%, at a distance from 50 to 100 meters - for sound metering 34% and light metering 48%, and at a distance over 100 meters - for sound metering 7% and light metering 18%.
And, finally, the 4th French army in the period from 18 to 31 July 1918 in the sectors of the 21st and 8th corps received the following results of determining the location of targets: sound measurement - 367 targets; light metering - 177 targets; tethered balloons - 25 targets; aviation - 56 targets; by other means - 2 goals.
From the above material, it can be seen that by the end of the First World War, by the number of identifiable targets and by the accuracy of work, sound reconnaissance came out on top - in comparison with all other types of artillery reconnaissance. In particular, the French sound metrists discovered the location of the German ultra-long-range guns ("Long Bertha"), which were shelling Paris.
However, there was such a great skepticism in the army teams in relation to the work of sound meters that only after the end of the war the accuracy of the information received by sound meters regarding the location of these long-range guns was confirmed.
