IMPROVEMENTS IN SOUNDING APPARATUS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Charles Ambrose McEvoy at the Office
of the Commissioners of Patents on the 24th January 1882.
CHARLES AMBROSE M'Evoy of 18 Adam Street Adelphi in the County of
Middlesex, "IMPROVEMENTS IN SOUNDING APPARATUS."
This Invention has for its object improvements in sounding apparatus.
My improved sounding apparatus operates by completing an electric circuit when
it comes into contact with the bottom.
There is a battery and bell or indicator of any suitable construction in the ship
or boat from which the soundings are taken and one terminal of the battery is
electrically connected with an insulated wire contained within the sounding line
whilst the other terminal is electrically connected with the external water.
The lead or sinker is cylindrical in form and is in two parts:--The upper part
has a hole through it axially sufficiently large for the sounding line to pass through.
The hole is enlarged at the upper end and forms a socket. A screw thread is cut
within the socket and it receives a corresponding plug. The parts serve to attach
the sounding line to the lead or sinker, the end of the line is passed through the
hole formed to receive it, a loop of it is laid around within the socket and the plug
is screwed down upon the loop.
The same part of the lead or sinker at its other or lower end is somewhat reduced
in diameter and the hole within it is enlarged to form another socket. A washer
or stout ring of soft india-rubber is accommodated within this socket, the sounding
line passing through the ring as it does also through a plug of vulcanite which is
screwed into the socket so as to compress the soft rubber ring.
These parts serve to form a water tight joint around the end of the sounding
line. The vulcanito plug is screwed to receive a metal cap upon the part projecting
from the socket and this cap when screwed on establishes contact with the
insulated conductor within the sounding line and it is provided with a contact stud
on its under surface.
The lower part of the lead or sinker is tapered at its upper end and terminates
at the top in a contact stud. It is connected with the upper parts by a cago
consisting of metal bars. The cage is fixed to the lower part but the connection
between it and the upper part is such as to admit of the contact studs approaching

page_text: and receding to make and break the electric circuit. There are slotted holes in the
upper ends of the bars forming the cage and through these holes pass screw studs
which are fixed into the upper part of the lead or sinker.
The two parts of the lead or sinker are also connected by a stout vulcanized
india rubber tube surrounding the cage; The tube having been sprung on is
securely fastened by a serving of wire.
Thus the water is effectively excluded from the cavity containing the contacts.
Sometimes I modify the construction and connect the lower part of the lead or
sinker with the upper part immoveable by a screw joint made water tight by a
simple washer. I have a cavity in the lower part in which I place mercury. When
the lead or sinker is turned on its side the mercury covers the contact stud
in the upper part of the lead or sinker and completes the electric circuit.