rength
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.
For the first reason, we found it necessary to put a pad of some kind
inside the knot--leather, linen, or a little tow or waste rope will do.
For the second reason we preferred knots in which the folds are least
sharply bent round each other; that is, in which the curves are large. We
therefore conclude that--1st. No knot, which is not absolutely necessary,
ought to be allowed to remain on the rope: 2nd. The tighter and harder a
knot becomes, the worse it is: 3rd. The more loose and open a knot is
made, the better it is:--and we append diagrams of those knots which we
found by experiment weaken the rope least. For Alpine ropes, only three
sorts of knots are ever required, and we suggest one of each kind:--No. 1
is for the purpose of joining two ends. No. 2 is for the purpose of
making a loop at one end. No. 3 is for the purpose of making a loop in
the middle when the ends are fastened. No. 4 is a knot, of which we give
a diagram in order that no one may imitate it. It is one of those which
most weaken the rope. The only one which seemed to be equally injurious
is the common single knot, of which no diagram is necessary. As the topes
which we have recommended are very liable to become untwisted, unless the
loose ends are secured, we advise travellers, in order to avoid knots, to
have the ends of every piece of rope bound with waxed twine. It should
also be known that it is very unsafe to join two pieces of rope by
looping one end through the other, so that when the jerk comes, they will
be strained across each other as two links of a chain are strained across
each other. Unless a pad of some kind divides the loops, one will cut the
other