This number fluctuated to some extent, for at least two divisions were drawn off from the siege to reinforce Oyama at the battle of the Sha-ho; but at no time can the total forces before Port Arthur have been less than 60,000, and then superiority in numbers to the defence gradually increased until from a proportion of two to one, it had reached the proportion of six or seven to one. This growing disparity, of course, was due to the fact that while the Japanese could replenish their exhausted ranks, the Russian garrison could not fill the gaps caused by wounds and sickness; while a further reduction of at least 5,000 men in the forces at Stoessel's command was made by the naval sortie on August 10th. That feat, of course, deprived Port Arthur of the services of the crews of all the vessels that escaped to neutral ports. [Illustration: JAPANESE SCALING FORT AT PORT ARTHUR.] [Sidenote: Capture of Forts] In the great assault of the 19th-26th August the Japanese lost 14,000 men, and succeeded only in capturing the Banjushan fort, which is east of the Urlungshan forts. General Nogi then settled down to steady siege operations, drawing his parallels nearer and nearer to the Russian main position, and capturing the all-important Kuropatkin fort early in September. This fort, which stands on Division Hill half-way between Wolf Hill and the harbor, not only commanded the parade-ground, but gave the Japanese the possession of the waterworks from which the garrison drew the main water supply. Up to this moment General Nogi's heaviest guns had been 4.7 and 6in. pieces of the naval type, and they had been quite unequal to the heavy guns of the position mounted in the Russian works. But now heavy siege guns and 11in. howitzers arrived from Japan, and immediately their effect began to make itself felt, so that by the 19th September another assault was resolved on. This was directed against three points of the ring of defensive works--against the metre-hill forts on the west, and (the outworks, as it were of the great Etseshan and Antszshan forts) against the advanced works of Urlungshan on the northeast, and against the lunettes in the Shuishi Valley which connects the Antszshan and the Urlungshan forts. At this last point some of the fiercest fighting of the whole siege took place. The Shuishi Valley was defended by a series of strong lunettes connected by advance works, within fifty yards of which the Japanese had advanced their parallels. On the evening of the 19th September four desperate assaults were delivered against the westernmost lunette. All, however, were beaten back. At dawn the assault was renewed with greater strength, and the western lunette was carried, mainly by the employment of dynamite grenades. The Russian garrison were driven out of the trenches, losing three quick-firers, four machine guns, and two mortars, but inflicting on the victors losses amounting to over 400 killed and wounded.