20 THE TWISTING OF CORDAGE. 
conversion into ropes of any length, or for weaving into cloth, 
without first undergoing some preparation. The natives of the 
great Eastern Archipelago join the ends of different fibres 
together by means of some adhesive substance, and thus form 
the “invisible knots” of an old author and obtain a thread, 
which, without spinning or twisting, is long enough for 
weaving. 
If this were practicable with all fibres, they might be joined 
together end to end, then laid side by side and formed into 
bundles, which might be wrapped round or tied at intervals, and 
form a rope in which the strength of each fibre would be re- 
tained. Some ropes thus made for the purpose of experiment by 
Duhamel, were found to be of great strength but of little 
durability. The outer case wore off, and the rope opened at 
the bendings, so as to let in water. This being retained, 
assisted the decomposition of the rope. 
It has been long discovered that we may obtain length by 
twisting fibres together, when they press upon each other, so 
that any single fibre is unable to overcome _the resistance, 
caused by'the friction upon it of surrounding fibres. It will then 
break more readily than slip out from the mass, By this 
means, a certain degree of compactness is also obtained, so that 
the infiltration of water is prevented, and the rope preserved 
from decomposition. Though a certain degree of twist is essen- 
tial, any excess is injurious; for a rope may be so twisted as 
to break in the operation. And therefore a rope, brought up to 
this point without breaking, would be unable to bear any 
further strain, or to support any weight at all, and consequently 
be useless, Great precautions are therefore necessary in twist- 
ing the fibres, so that they shall retain as much as possible of 
their original strength, and be preserved from sustaining any 
further injury. 
In making a rope, the first operation is to twist a certain 
portion of the fibres into a thick thread, which is called a yarn. 
These yarns vary in size, from one twelfth to a little above 
one ninth of an inch in diameter. These yarns are then warped, 
or stretched 80 that they may bear any strain equally. The 
next process is to twist a number of yarns, say from fifteen to 
twenty-five, into a strand. The twist of the strand is in an 
opposite direction to that of the yarn of which it is composed, in 
