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Sounding, be admitted by every Teaman •, and it is ratber Angular,
v*“ " v that no other method than the common lead has hither¬
to been brought into ufe ; as its imperfections are very
generally acknowledged.
“ Many veffels have been loft, by depending upon the
foundings taken in the ufual way. The difficulty of ob¬
taining the true perpendicular, and the uncertainty as to
the exadt moment when the lead ftrikes the bottom, up¬
on which the accuracy of the relult depends, mult al¬
ways prevent the poffibility of obtaining the true depth,
while the ihip has any confiderable way upon her. In¬
deed, it has been acknowledged by experienced Teamen,
during fome experiments, made at various times, in the
river Merfey, that they could not depend upon the com¬
mon lead, when going five or fix knots in the hour, m
ten or twelve fathoms of water. When the depth is
confiderable, the veffel muff be hove to, which is an ope¬
ration attended with great lofs of time, and fometimes
confiderable injury to the fails-, and during a chafe, this
inconvenience muff be particularly felt.
“ True foundings may be taken with this machine in
thirty fathoms water, without the trouble of heaving the
veffel to, although Ihe may be going at the rate of fix
miles in the hour. True foundings may alfo thus be
obtained in very deep water, where it is not poflible to
take them by the common lead.
Plate “ Fig. i. reprefents the founding machine, a is the
cgccxcvii. founding weight, containing a regifter, i, 2, with tw-o
I* dials : the hand of the dial I makes one revolution when
the weight has defeended twenty fathoms, the other re¬
volves once when the defeent amounts to five hundred
fathoms. A rotator, b, fimilar to that attached to the
log, communicates with the wheel work of the dials
l, 2, by means of the rod c, on which there are three
univerfal joints, 3, 4, and 5. This rod is fupported du¬
ring the defeent of the weight, by the drop, d, at the
end of which is a fork, 6, and a friftion wheel, 7.
“ When the machine is to be ufed, a founding line is
fattened to the ring, e ; and one of the vanes of the ro¬
tator is flipped into the fpring 8 : the rotator will then
be in the pofition indicated by the dotted lines, x. I he
indices muff be fet at o, and the cover or lid, jT, be fhut.
The machine muff then be projected perpendicularly
into the fea, As foon as it reaches the furface, the re¬
finance of the water forces the dotted rotator, x, out of
the fpring 8, and it affumes its perpendicular dire&ion
as reprefented by the rotator b. As the machine de¬
scends, it is evident the rotator will revolve, and its mo¬
tion be communicated freely paft the fri£tion wheel 7,
and the univerfal joint 5, to the wheel work of the dials
I, 2, and thus indicate the fpace paffed through in fa¬
thoms. When the machine has arrived at the bottom,
the rotator, as it is no longer buoyed up by the reaflion
of the water, will fall to the bottom, quitting the fork
of the drop d, which will alfo fall from its horizontal
pofition, and in its defeent, by means of the locking rod
,9, prevent the rotator from revolving as the machine is
drawn up. When at the bottom, the rotator will be in
the pofition of the dotted lines y.
“ This machine, fimple in its conftruftion, and fcarcely
more liable to accident than the common lead, afccr-
tains, with tfie utmoft precifion, the perpendicular depth,
by the mere a6t of defeent through the water. No mif-
take can arife from that common fource of error, the
drift or lee-way of the Thip during the time of defeent y
nor does an operation of fuch importance depend upon Sound
the uncertain fenlation cauied by the lead linking the'""'“Ye
bottom, on which the accuracy of the common log al.
together depends, and which, it is well known, frequent¬
ly and materially mifteads the beft feaman : for though
a thoufand fathoms of line were laid out, in the fmalleft
depth of water, no inaccuracy could arife, as the perpen¬
dicular depth, at the point of heaving, would be regi-
ftered on the index. The only inconvenience experi¬
enced would be the additional labour neceffary for haul¬
ing in the excefs of line. The moft inexperienced per-
fon may ufe this machine, without rilk of error, in the
moft turbulent fea, and during the night.
“ The advantages already enumerated would render
the founding machine of great importance ; but there
are other properties of ftill more confequence.
“ To heave a Ihip to, in order to obtain foundings, on
a lee ftiore, in ftormy weather, is a very difagreeable
operation, attended with much trouble, and lofs of way;
alfo with confiderable danger to the Thip’s fails j indeed,
it would often, under fuch circumftances, be attended
with great hazard to the fafety of the fhip. To avoid
thefe unpleafant confequences, the mafter fometimes
adopts a meafure, which he conceives to be the lefs ex¬
ceptionable alternative, by running on without founding
at all.
“ To prove howr much inconvenience and danger are
avoided by Maffey’s lead, it is enough to ftate, that
foundings may be taken in depth from 60 to 80 fathoms,
while the (hip is under way, at the rate of three miles
an hour j and as the rate of failing may be ftill materi¬
ally reduced, without entirely flopping the veffel, or al¬
tering her courfe, fo may foundings be had, to any depth
required, while (he is under way.
“ In order more clearly to fhow the fuperiority of this
machine, and make it apparent, that the quantity of
ftray-line veered out does not at all affedl the truth of the
refult : fuppofe the common lead thrown from the mizen
chains of the Ihip, which may be reprefented by the
point a of the triangle a b c, (fig. 2.), and that the ftiipfig, 2,
has moved forwards through the fpace equal to the line
b c, while the lead has defeended through the line a c ;
it is evident, that it is impofiible, in this cafe, to afeer-
tain the exa£t depth, as a quantity of line, equal to a b,
would be paid out, whereas the true depth is equal only
to the line a c, which is much lefs. But the cafe is very
different when the patent founding machine is ufed, as
the operation ceafes when it has reached the bottom j
nor is the ftray-line, a b, whatever its length, at all taken
into the account.
“It has been extremely difficult, and fometimes im-
poffible, to obtain foundings in very deep water with the
common lead, whifch may perhaps be thus accounted for.
The common line Avhicli is ufed for founding, though, if
left to itfelf, it would fink in water, yet its defeent would
be much flower than that of the lead, feparately ; it
confequently follows, that the lead muft be fo much im¬
peded by carrying the line with it, that when it does
reach the bottom, there will be fcarcely any fenfible
check to enable the feaman to know the precife mo¬
ment. Indeed, if he can afeertain even this to a cer¬
tainty, he ftill cannot depend upon the truth of Ins
foundings ; for if there be the leaft drift or current, the
line itfelf will affume a curve, fimilar to that of the line
of a kite in the air. Thefe two oaufes will always ope¬
rate

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