rection than those on its outside, all the violence of 
the strain will fall upon the central lines of fibres, 
while those on the outside will scarcely feel it at all. 
Taking the sum of the fibres or yarns, therefore, 
will give no clue to the strength of a rope as they 
are usually made; and no rope so made can possess 
a strength anything like equal to what the sum of 
the yarns would produce or support if they could act 
singly. The late Captain James Huddart, of the 
British East India company’s service, contemplating 
the imperfections to which large ropes were liable, 
from unequal or imperfect twisting, and the unequal 
strain to which the individual yarns were exposed in 
their common arrangement, invented a most admira- 
ble and simple contrivance which he called a regu- 
lator, and for which he obtained a patent, by means 
of which different quantities of yarn was supplied to 
the different parts of tae strand while it was twisting 
or laying. ‘That yarn that went to form the centre 
of the strand, never deviated from its right lined 
direction, while a larger quantity was given out to 
the outsides which had to pass obliquely, and conse- 
quently through more space, and by this means, and 
using a less hard twist than had formerly been re- 
sorted to, he produced the most perfect and uniform 
ropes, which were so perfect as to the equilibrium 
of their own parts, that they had no tendency to 
twist or recoil even when quite new; and on sub- 
jecting his ropes to experiment, it was found that 
instead of losing any of the original individual strength 
of the fibres, they assisted each other, and produced 
an aggregate power greater than their primitive one. 
Since the éxpiration of his patent, some of the prin- 
cipal rope-makers have adopted his plan of working, 
the advantages of which soon became known among 
nautical men. 
The tarring of ropes can evidently add nothing 
to the absolute strength of the materials of which 
they are formed ; and yet it is thought to render 
ropes stronger. If it does so, it can be on no 
other principle than that the tar cements the 
fibres together, and thus causes those parts to 
act conjointly, which without such assistance 
might have acted separately. The great use of 
tar is, however, to exclude moisture and prevent 
the rope from rotting, which it would do in damp 
situations ; and it likewise prevents sand and 
grit getting into the inside of a rope, and these 
are very detrimental to ropes that are kept in 
constant motion, as they fret and wear away the 
internal fibres. 
The rule that has been established by practice 
for ascertaining the strength of new ropes made 
of the best hemp, without tar, is that they should 
support one-fourth of the square of their circum- 
ference taken in inches, in tons. Thus, if a rope 
is 2? inches in diameter, its circumference may 
be taken at 9 inches, the square of which is 81 
inches, and dividing this by 4, the quotient 
would be 204 tons, which such a rope should bear 
upon a fair and even strain; but as all ropes are 
subject to jerks and concussions, it is better to 
take a fifth instead of a fourth of the square of 
the circumference, and this would reduce the 
above named rope to 161 tons, Moreover as 
this rule applies to new ropes, made of the best 
material, and much inferior hemp is used, or 
cheaper materials of less strength are almost 
constantly mixed with it, and a rope is expected 
— 
ROPE. 
to last and wear a considerable t'me; so itis not 
prudent to put more than half this load upon a 
rope that is in constant use, because if strained 
to its full extent in the first instance, it will soon 
give way by use. The rule which Captain Hud- 
dart established in his rope manufactory, and 
upon which he would warrant all ropes made 
there, was to multiply the square of the circum- 
ference of the rope by 900, and this would give 
the number of pounds avoirdupois which the 
rope would sustain with safety. If we take the 
same example as before, of a rope having 9 inches 
circumference, then 9?= 81 xX 900 = 324 tons, or 
rather better than a third more than a rope of 
ordinary formation would bear. 
M. Du Hamel states that tarred rope is much 
weaker than that which is untarred, their diame- 
ters being equal, and he gives a table of com- 
parative experiments made with three inch rope 
in proof of this assertion, in which the tarred 
rope is in every instance greatly inferior in 
strength to that without tar, but he assigns no 
reason for this apparent phenomenon, although 
it is well understood by every rope-maker. They 
usually demand the same price for tarred rope 
as for that which is clean, and even sometimes 
make a favour of charging nothing for the tar 
and trouble of applying it. But the fact is, the 
tarring is always performed upon the separate 
yarns, by drawing them through a kettle of boil- 
ing tar, before they are twisted into strands. 
The hot tar swells the fibre, and a quantity of it 
adheres to each of them, so that the diameter of 
the yarn becomes sensibly increased, and of 
course a much less number of yarns become ne- 
cessary to form a rope of the same diameter, 
than if clean hemp was used. This is quite 
sufficient to account for the deficient strength of 
tarred ropes; but if, instead of comparing the 
ropes by their diameters, they were compared by 
the number of yarns they contained, then the 
tarred rope would, it is believed, have the ad- 
vantage. The inexperienced purchaser when he 
buys a tarred rope, does not usually consider 
that in each pound of rope he buys, he gets about 
14 oz. of hemp and 2 oz. of tar, which are both 
sold for the same price, although hemp is at 
least sixteen times more costly than tar. M. Du 
Hamel, however, goes on to state, that it is de- 
cided by experience that white cordage in con- 
tinued service, is one-third more durable than 
tarred; that it retains its strength much longer 
while kept in store; and that it resists the ordi- 
nary injuries of the weather one-fourth longer. 
These observations deserve the attention of prac- 
tical men, being very important. There is, how- 
ever, a reason why tarred ropes should be used 
in particular cases, such as the standing rigging 
of ships, or that which does not require to be 
run over pullies or to. move; such as the main- 
stays, fore-stays, and shrouds, by which the masts 
of vessels are held and maintained in their ver- 
tical positions. The reason is that all untarred 
