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The crossing points are strengthened by ligatures of fine twine.

VALVES FOR WORKING THE BALLOON.

The circumference of the net, all the way up, consists of 192 meshes, the dimensions of which vary according to the area of the zone they are to cover. These meshes, the number of which is no less than 19,000, represent a length of twine amounting to nearly 16,404 yards.

The lower part of the net is formed by a system of three zones of crowfeet or cringles, each zone reducing, by one-half, the number of meshes composing the next upper zone.

The first row of crowfeet is mounted on thimbles of nickeled brass, the second and the third on wooden pulley-blocks, having sheaves of lignum vitæ; and forty-eight suspending cords, each fitted at its end with an eye, complete the net and form points for tying it to the retaining ring by means of toggles. These suspending cords have a diameter of ⁷⁄₁₀ inch, and a bearing-strain of no less than 6,613 lbs.

The net thus constituted weighed 776 lbs. In order to preserve the cordage from moisture it was impregnated with vaseline, except in the upper part, which was covered with a projecting cover of varnished silk; after this operation the weight of the net was 974 lbs.