was securely attached to a pile driven a short distance above and in the prolongation of the pier, which pile was nearly sawed off. When driven by the pile-drivers sufficiently it was broken off, and the end of the included pile thus anchored to the bottom; the other was spiked to the pier, as shown in the sketch below.

The river deepens to 16 feet about 1,000 feet from the north shore, and then to 30 feet for a distance of nearly 180 feet, and then decreases rapidly to the shore-line. At the channel a draw of pontoon-boats was made 180 feet wide. The lumber which was used in the construction of this bridge was obtained from the engineer depot saw-mills.

February.-There were additional river batteries on the south side of the James, constructed and armed with 100-pounder gun, as an additional protection against another rebel raid of iron-clads. During this month and early in March the engineer force of the army decreased rapidly, owing to the expiration of their term of service.

March.-There were at this time less than 300 effective men for duty, and but a small number of these were engineer soldiers proper. Repairs of the batteries were constantly going on. To obviate the effects of winter weather, platforms were relaid, magazines drained,

[MAP.]

and their cover renewed and thickened, and generally the lines of the army put in good defensible condition.

The mules belonging to the pontoon train were worked continuously at the saw-mills during the winter, and only relieved when directed by Major-General Barnard, the engineer of the combined armies operating against Richmond, to be used in preparing four pontoon trains for active service and marching. New mules were obtained, and every effort made to break them to harness in time. The whole artisan force was put at work to repair and strengthen the wagons and boats. Finally orders were issued to take a train of but fifteen canvas boats, which was ready for the march on the day specified. The engineer force was divided; one part under Bvt. Major W. R. King, U. S. Engineers, remained with General Weitzel's forces, and continued the erection of a defensive line until the news of Lee's surrender reached the city. They also built a pontoon bridge joining Richmond and Manchester 2,400 feet long, upon which afterward the Armies of the James, the Potomac, Sherman's army, and Sheridan's cavalry crossed. The engineer force with the moving column consisted of six companies of engineers and one of pensioners.l

13 R R-SERIES III, VOL V