1. MANILLA HEMP. Weight of 20 yards, 48 oz. Advantages--Is softer and
more pliable than 2. Is more elastic than 2 and 3. When wet, is far more
pleasant to handle than 2 and 3. Disadvantages--Has a tendency to wear
and fray at a knot.
No. 2. ITALIAN HEMP. Weight of 20 yards, 43 oz. Advantages--Is less bulky
than 1 and 3. Is harder, and will probably wear best, being least likely
to cut against rocks. Disadvantages--Is much more still and difficult to
untie than 1 and 3. When wet, is very disagreeable to handle, and is apt
to kink.
No. 3. FLAX. Weight of 20 yards, 44 oz. Advantages--When dry, is softer,
more pliable, and easier to handle than 1 and 2, and will probably wear
better than 1. Disadvantages--When wet, becomes decidedly somewhat
weaker, and is nearly as disagreeable to handle as 2.
Knots.--There can be no doubt that every knot in a rope weakens its power
of resisting a sudden jerking strain. How great a loss of strength
results from a knot we cannot undertake to estimate, but that the loss is
a very serious one the following statement will show: these ropes which
we report will resist the strain of fourteen stone falling eight feet,
will not resist it if there is a knot in any one of them; or even if the
knots used in attaching them to the point of support, or to the weights,
be roughly or carelessly made. The rope in these cases breaks at the
knot, for two reasons; partly because of the folds, as they cross in the
knot, are strained suddenly across each other, and one of them is cut
through; and partly because the rope is so sharply bent that the outer
side of each fold in the knot is much more stretched than the inner side,
so that the strain comes almost entirely upon one side only of each fold.
Pages:
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83