Geoscience Reference
In-Depth Information
latitude and longitude of each lighthouse, the times would vary, of course, the further
north or south you were; it was as precise as that.
Evenaslateas1974,morethanafewlightswerestillrunonparaffin,justlikeagiant
Tilley lamp and the mechanism which operated them was mostly hand-wound as well,
similar to clockwork
.
Basically, the light, whatever its source, was fixed inside a large
series of lenses. These lenses rotated around the light, giving the station its identifying
flash; some ran on roller bearings and some floated (literally) in a bath of mercury. The
'machines'ranatvariousspeedswhichdifferedfromlighthousetolighthouse,thusgiv-
ingeach its own'identity', which wasofcourse printed ontheAdmiralty charts carried
by all shipping, thus enabling the mariner to fix his position. As a very rough rule of
thumb, in Scotland one generally could count on a major or minor light being situated
around the coast every 20 miles or so.
Each machine was set to rotate at a specific speed in order to generate its own flash,
and the prime duty of each lightkeeper was to ensure that the light was exhibited at the
proper time and that it maintained its proper identity. A large weight was suspended at
the end of a chain, or a steel cable attached to the machine. Initially a keeper would set
the lens in motion, after lifting the blinds on the astragels (the windows right at the top
of the lighthouse). Then, if it was a paraffin light, the keeper pre-heated the mantle by
lighting two wicks in a small container of methylated spirits, opened the valve and then
ignited the vapour using a large taper. The flame was then adjusted and the light was in
operation. In the lightroom, there were two containers, one of compressed air and one
ofparaffin.Theappropriatevalveswouldbeopenedtoensureasteadysupplyoffuelto
thelightandthepressurewaskeptgoingviaanattached stirruppump.Itwasimportant
to make sure the methylated spirit wicks were extinguished and the machine was run-
ning at the correct speed after winding it fully. Then, depending on circumstances, the
keeper would maintain their watch in the lightroom, as they were supposed to do, or go
back down all the stairs again, which many of them did.
Some machines ran for thirty minutes before they had to be rewound, some ran
for forty or forty-five minutes and some ran for an hour. They all varied. Rewinding
brought the weight back to the top again and whilst this was being carried out it was
geared to keep rotating.
Theultimate sinwasto'standthelight'ortoallowittoexhibitafalsecharacter.Do-
ing so meant instant dismissal with the loss of not just the job but your home as well.
It was a sobering thought in the broadest sense, as drink was also the downfall of more
than one lightkeeper from the time the role was created.
Maintaining the watches appears more complicated than it actually was. One man
came on at 6 p.m. and was on duty until 10 p.m., putting the light on if such action fell
betweenthesetimes.Hewouldthenhandovertothesecondman,whosedutywasfrom
