 Check out the bookstore at IRBS.com |
|
|
|
|||||
|
||||||
From: Jared Sherman (no email)
Date: Sun Jun 20 2004 - 22:06:18 EDT
Ritchie are in Pembroke, MA now at www.ritchienavigation.com/ and you could
give them a call to enquire.If you can send them a digital photo they may be
able to identify the compass.
The two issues are that the fluid be the right viscosity, and that it not
dissolve anything. My impression is that the mysterious "compass fluid" sold
at genuine marine prices is what we call kerosene in the States, aka
"paraffin oil" in the UK. Much thinner than mineral oil. Of course kerosene
comes in many grades, so the "compass fluid" probably is somewhat more
refined than what you'd buy at a fuel station.<G>
----- Original Message -----
From: "Trevor J. Kenchington" <>
To: <>
Sent: Sunday, June 20, 2004 5:25 PM
Subject: Refilling a compass, was: Compass tilt
Jared wrote, in response to George:
> <Johnson's baby oil, straight from the bottle,>
>
> Johnson's confirm this to be simple mineral oil, with fragrence added.
> Generic mineral oil from the pharmacy is sold unscented, typically at less
> than half the cost. Of course, then the compass might not smell as
sweet.<G>
I have a rather nice older, brass box-compass, less its box, picked up
for next to nothing at a flea market years ago. However, its fluid had
been drained off, making its card very unstable and the compass quite
useless as anything but decoration. Can anyone suggest how I should
determine whether it should be refilled with oil (Johnson's or
otherwise) or spirit?
I figure that getting a new box made would easy enough if I could refill
the compass itself. Maybe I would also need to restore the seals to keep
the fluid in. Still, the result should be prettier, better quality and
likely cheaper than buying a new compass of the same type.
This compass is identified as "Ritchie, Boston". It is marked in quarter
points but also in degrees, from 0 to 360. I assume that the latter
(rather than markings of 0 to 90 in each of four quadrants) dates the
instrument to post-1920 but perhaps American practice turned to the
360-degree notation before the British did (and/or perhaps my memory of
when the Royal Navy abandoned quadrantal notation is wrong).
Trevor Kenchington
--
Trevor J. Kenchington PhD
Gadus Associates, Office(902) 889-9250
R.R.#1, Musquodoboit Harbour, Fax (902) 889-9251
Nova Scotia B0J 2L0, CANADA Home (902) 889-3555
Science Serving the Fisheries
http://home.istar.ca/~gadus
|