G - 3 reported that the division artillery fired a "gas concentration on an active battery" on both 16 and 17 March and again on 28 March, but these are the only references in the daily reports for the period at Ansauville that the division retaliated against the enemy with gas fire.
Butler's journal indicates much more frequent use of gas, and this is confirmed by the artillery brigade summary which indicates that the brigade fired gas shells on 39 of 66 of the days (1 February - 4 April) while in the Ansauville sector. On some days it fired no more than 20 rounds. The greatest number of rounds, 4,411 were fired for raids on 11 March. A1together, at least 9,251 rounds of gas were fired, including 4,002 155-mm rounds, 3,257 75-mm rounds, and 1,992 75-mm rounds fired by the French artillery - most of it phosgene, with some proportion of cyanogen chloride. The total of 9,251 does not include the 6,000 rounds probably fired on 4 March, but for which no positive record remains (see narrative, p. 30).
During February, the division was allowed less than 100 rounds of gas shell per day. In March, as a brigade memo shows, this was increased and each 75-mm battery was authorized to maintain 2,780 HE, 220 shrapnel, and 600 gas shells at its position, as well as 1,500 HE and 300 gas shells at each 155-mm battery position.106
General Bullard was to say that "The gassings' the enemy was giving us were more than answered. The French gas which we were using was very deadly and the enemy had a wholesome fear of it." While General Bullard's statement was not strictly true, its general accuracy was reflected in the G - 3 report in late March that The anxiety of prisoners [captured in a raid on 28 March] to take their gas masks with them showed the effectiveness of our gas bombardments."107
As interesting as the allotment of gas shells by the French to a new and untried American division was the willingness of the division to use it. In the months to come, the divisions in the field were either to complain that they could get little or no gas shell, or in some cases were to show a marked reluctance to fire such gas shell as was allotted to them, in the hope that the enemy would not return the gas fire. All who like the 1st Division recognized the necessity of opposing gas with gas and valued its employment in tactical operations, were to complain that they could not get the quantities of gas shells they requisitioned.
It was, of course, the repeated touching up" of the enemy artillery with gas on the Ansauville front that led to retaliation and to the high incidence of gas casualties among the artillerymen. The result was that the greater number of gas memos and instructions issued by the division were directed to the artillery rather than to the infantry.108 Supplementary instructions to AEF pamphlet 253 also tended to show special concern for the artillery. In general it may be said that the requirements of alternate battery positions, relief teams, and maintenance of complete individual gas protective equipment for artillery personnel were developed on the assumption that the artillery was the principal target of enemy gas fire and that it would have to continue to fire during and after gas bombardments while the infantry remained in gasproof dugouts until any gas in their area had dissipated. It was some time before the frequency of gas attacks on the infantry demonstrated that their gasproof dugouts were gas traps more often than not.
Events in the winter and spring of 1918 served to increase the concern for the protection of artillery. The period was marked by rapid changes in methods of gas warfare, first as a result of developing doctrine by the Germans in the use of mustard gas, and by their introduction into the field of the arsine gases. One result, apparently, based on the enemy's use of
gas and their own use in retaliation, was the formulation by the French of the doctrine that "gas shells are most often used for the neutralization of batteries, giving the best results for this purpose."109
Both Von Hutier at Riga and van Bulow at Caporetto, in September and October 1917, demonstrated the effectiveness of a short intensive preparation with gas on the opposing artillery and massive high explosive fire on the infantry just before an attack. In the spring offensives of 1918, Ludendorff was to improve on this tactic by using great quantities of the new arsine gases, following them with lethal phosgene. By employing these gases on the artillery and hitting the infantry on his front with HE from massed minenwerfers, he created the gaps in the line for his deep penetration and maneuvers of rupture,110
Through the winter and spring of 1918 mustard gas continued to be used in large quantities principally to interdict terrain and neutralize opposing battery positions. One of the last large-scale uses of mustard gas was the five-day saturation with over 250,000 yellow cross shells, on 11 - 16 March, of that portion of the British front outside the attack zone, prior to the
offensive on 21 March.111 But in the final months of the war, in their efforts to conserve their dwindling supply, the Germans discovered the effectiveness of mustard gas, as well as of the harassing and lethal gases, in small daily concentrations on troop positions.112
With the opposing infantry as the principal target, the Germans developed the Gas Uberfall or burst of fires a short surprise fire on small targets; the Verseuchungsschiessen or zone concentration fire on terrain important for the enemy to occupy; the Schwadenschiessen or sheet fire, for use against troop areas; and HE-gas fire, against moving objects.113 All these methods were based on multiples of 100, that is, 100 rounds per target, 100 rounds per hectare, 100 rounds per hour, with the result that German gas attacks in the closing months of the war were made with gas shells by the thousands, at most, and no longer by the hundreds of thousands.
If these German developments had their impetus in conservation of gas ammunition, they were also made necessary by the insistence of the AEF on conducting their operations by open warfare methods. And the size and inexperience of the American divisions made their infantry rather than their
artillery the logical gas target.
The infantrymen of the AEF were to have no reason to question the effectiveness of the relatively small gas attacks that they experienced, and no doubt about the intended target. But so far as the 1st Division at Ansauville knew, the principal gas target was the artillery, not the infantry.