( 316 )

Two pontoon carriages.

4 crabs or small capstans.

The rope-work was put together in the pontoonhouse at Elvas, in the following manner:—Twobeams, (i), B B, fig. 5 and 6, plate 8, laid ontrestles 4 feet high, placed 90 feet asunder, werefirst secured to the end walls of the house bytackles and braces. The 6£ inch cable ( 2 ) wasthen stretched in eighteen lengths, or rows, roundthe beams B B, with a uniform, moderate strain,such as to admit of the parts or row's of thecable being drawn together by strong lashings,at alternate points, and formed into a body ofnet work, fig. 6; the two outside rows of thecable being first steadied by tackles to theside walls of the house, to resist the inwardstrains resulting from the process, and to retainthe net work of uniform width, throughout.

Cross beams ( 2 ), C C, fig. 6, and profile underfig. 7, having channels cut in them, and searedto smoothness with a heated iron, (the arm ofan axletree,) were then laid on the net work,each notch receiving its corresponding portionof rope, and firmly lashed by spun yarn ( 16 ) atall the crossings.

The beams, D, fig. 6, were prepared in a novel