The impression that the Chemin des Dames had been conquered was not removed until it really was gained by Pétain five months later; but there was contrast enough between the promises and the achievement to produce the deepest depression in France. On 28 April Pétain was appointed chief of staff and on 15 May commander-in-chief in succession to Nivelle, while Foch became chief of staff. Little was wisely revealed abroad of French despondency or the effect of the disappointment on the moral of the army. But French journals began to clamour for unity of command of all the forces in France under a French generalissimo, pour épargner du sang Français, as one of them expressed it; and prudence constrained the higher command to revert to those limited objectives which Nivelle had abandoned. Joffre was sent to the United States to place the situation before the sister-republic; and but for American intervention France would have been nearer a peace of compromise in May 1917 than at any previous date in the war. The second battle of the Aisne gave rise to that miasma of défaitisme, associated with the names of Bolo and Caillaux, which enfeebled the spirit and effort of France until they were revived by Clémenceau's vigorous stimulants. Haig was also laid under an obligation to relieve the pressure and gloom by prolonging his Arras offensive and seeking to extract more from his victory than it would yield; and the second phase of that battle was fought under a shadow and under constraint. But if it resulted in serious losses, it brought some additions to our gains of ground. On 23 April Gavrelle and Guémappe were captured after desperate fighting; and on the 28th an advance was made at Arleux and Oppy. On 3 May the Canadians took Fresnoy, and the Australians trenches at Bullecourt, but the Germans kept up a series of stubborn counter-attacks, especially at Fresnoy, Roeulx, and Bullecourt, and Fresnoy was lost on the 8th. On the 14th we completed our capture of Roeulx, and on the 17th that of Bullecourt. The fighting died down, towards the end of May, and the scene was shifted farther north in June to the Messines-Wytschaete Ridge. During the month of the battle of Arras we had taken over 20,000 prisoners, and the French claimed more on the Aisne. We had also bitten into the Hindenburg "line." But that line had not been broken, mainly because it was not a line, having instead of none a breadth of several miles; and, apart from the important Vimy Ridge, the German position had not been greatly shaken. The warfare was one of attrition, and the true test was that of wastage, which can only be used when the losses on both sides are exactly known. There was evidence that the Germans were feeling the strain, but so was the Entente, and the influx of troops from the Eastern front, which began in April and was felt in the Arras battle, would more than compensate for the excess (if any) in German losses.