In protest at this ridiculous decision I'm going to take part in the re-creation of the most famous walk ever made along the banks of the Royal Canal. On the 16th of October 1843 Sir William Rowan Hamilton took a stroll down the canal into the fourth dimension. That journey is repeated by a group of devotees every year on the anniversary of that date - here's the story of why:
(From Chapter One “Beginnings”)
Broom
Bridge is sometimes rendered as “Brougham Bridge” because it was constructed to
allow the passage of Brougham carriages, a one horse vehicle commonly used as a cab. In truth it
was named after one of the founding directors of the canal corporation, just
like many of the canal’s Dublin bridges.
The connection to carriages is real though – the bridges did carry a
substantial amount of such traffic. In
addition to carriages Brougham Bridge also carried walkers from the outskirts
of the city to the centre. It was while
enjoying just such a stroll that Sir William Rowan Hamilton had a moment of
inspiration.
Hamilton
had long been considered one of the premier scientists of his age. Recognised as a genius early in his life he
had, by 1835, attained a prime position (and an accompanying knighthood) within
the Royal Academy, at only 30 years of age. This isn’t a maths class, but a short
explanation of Hamilton's greatest achievement requires a bit of math history. In mathematics there is the concept of
“complex numbers” which allow you to plot out where the intersection of two
points will occur in two dimensions. As
a very simple example think of when you look at a map and it says to look for
something at point “A-4” and so you count one square one way to “A” and then 4 the
other to get to the desired point. There
is a very simple equation to express that mathematically.
Hamilton
was fascinated by the prospect of extending that concept to three dimensions
(imagine if the map I just described was made out of paper mache’ so that
hills and mountains were depicted as well).
He wanted to describe mathematically a point that had length, width and
depth, and it was not proving easy to do get that done.
Hamilton even related that his kids would tease him about it at
breakfast. Then – on 16 October 1843
Hamilton went for a walk in to town with his wife. While crossing the arch of Broom Bridge he
had a “eureka moment” and realised that he could postulate a three dimensional
plot if he assumed the existence of a fourth dimension. Terrified that the inspiration would leave
him he interrupted the walk and inscribed the resulting equation on the stones of Broom
Bridge itself.
His
discovery, which he termed “quaternion multiplication” eventually provided the
mathematical basis for navigable spaceflight (it is how scientists are able to
plot the course of a spacecraft to the moon or Pluto from Earth) and also
addressed the concept of multiple dimensions which was later explored by
Einstein and others when developing space-time theory. And it all started at Broom Bridge, on the
Royal Canal. Today you can find the event commemorated on a plaque embedded in the bridge, which reads:
Here, as he walked by
on the 16th of October 1843,
Sir William Rowan Hamilton,
in a flash of genius, discovered
the fundamental formula for
quaternion multiplication
i² = j² = k² = ijk = -1
& cut it on a stone of this bridge
on the 16th of October 1843,
Sir William Rowan Hamilton,
in a flash of genius, discovered
the fundamental formula for
quaternion multiplication
i² = j² = k² = ijk = -1
& cut it on a stone of this bridge
Every
16th of October Hamilton’s historic walk is repeated by a cadre of
loyal devotees who follow the original path along the canal. These walks will
typically draw people from all over the globe and have included some scientific
superstars like Murray Gell-Mann, who won a Nobel Prize for describing a unique
sub-atomic particle, which he dubbed a “quark”, a name he got from reading
James Joyce’s Finnegan’s Wake. This was the first description of such a
basic component of matter – and also the first known instance of someone
actually reading Finnegan’s Wake.
Next, in a section of the canal outside of Enfield I found the opportunity to talk about some of the furry critters you might run across while on the journey.
(From Chapter Four "Many Rivers to Cross")
At Kilmore the path changes over
to the north side of the canal, requiring you to cross the bridge. There is a bit of a blind curve here so be
careful, particularly if you are travelling in a group. Once you get to the new pathway it will
become immediately apparent that this stretch is going to be different. Gone are the wide grassy tracts or paved paths
you’ve become used to since Fern’s Lock.
Instead this is a narrow wooded trail that will often barely have room
for a single person. In point of fact
the first time I ever went this far out the canal I ended up turning back from here
when I ran into a cross country footrace that was going the opposite way –
there was just too much traffic. While
I’d never want to see the trees here damaged there is scope to widen this
pathway and make it a bit easier to navigate.
In the meantime I’d recommend just enjoying the trip through the
forested section, especially since a definite reward lies at its end.
One of the benefits of entering
this type of habitat is that the presence of trees offers an opportunity to see
a much wider variety of wildlife. The
chance of seeing squirrels feeding in the treetops, for instance, only arises
in the event that you actually have trees above your heads. By the way - at this point in the journey, if
you do see squirrels, you’re probably going to see the grey variety, which is a
story in itself – for grey squirrels are not native to Ireland. How they got here is a bit of a cautionary
tale. In 1911 the Duke of Buckingham
sent a “wicker hamper” full of grey squirrels to the wedding of a young woman
from Castle Forbes in County Longford.
When the hamper was opened the squirrels leapt out and headed for the
trees, as squirrels are wont to do. From
that single event the grey squirrels went forth and multiplied (as squirrels
are also wont to do). This has had a
somewhat disastrous effect on the population of native red squirrels in
Ireland. Evidently being smaller and
cuter doesn’t cut the mustard in the Darwinian sense and the larger, hardier
greys have virtually wiped out red squirrels east of the Shannon. That natural river barrier seems to have held
up thus far, so – if you should happen to see a grey squirrel while travelling
along the Royal Canal please leave him be and do not take him along as a
wedding present to anyone living west of the canal’s terminus.
Squirrels of any variety aside –
there is a much wider selection of wildlife on view along the canal. In particular the section following Kilmore Bridge
gives you the opportunity to view a number of the canal’s non-human
residents. Let’s discuss the mammals
first, since, other than the domesticated pets, horses, cows and sheep that you
may run in to along the way they are probably the most difficult to easily view.
Almost all of the furred
inhabitants of the canal side are either fully nocturnal or primarily active
around twilight or dawn. That means
you’ll have to be lucky or starting/finishing your ride in semi-darkness to
really have much chance of seeing them.
The one major exception to this rule would be rabbits and hares, who can
often be seen in the fields or darting across the pathways during the middle of
the day. The hares are especially interesting
as their behaviour varies significantly throughout the year. During the height of breeding season the
males become much more aggressive and will often be seen darting around
establishing their territory. As this
rushing about takes place most often during the spring months you get the
expression “mad as a March hare”. You’ll
know the difference between rabbits and hares mainly by way of the fact that
hares are much bigger.
The rest of the canal’s mammalian
inhabitants will be evident mostly because of the clues they leave along the
way. For foxes this will often be spoor
or a pile of feathers from the previous evening’s meal. For badgers you’ll possibly see a pathway
through a hedge or the opening to a burrow (or “sett”). For the evidence of hedgehogs, wood mice and
shrews you’ll have to watch to see where the leaf litter has been stirred up in
their search for worms and slugs. If you
see some evidence of hunting having taken place, like bones or feathers, it
isn’t always down to foxes – stoats, mink or pine martens could be to blame as
well.
There is another Irish mammal
that prefers the twilight – and if you’re out around that time you have a
really good chance to see them. These
are bats – and the insect population, together with the old stoneworks and farm
buildings near the canal make it an ideal habitat for these creatures. Ireland
is home to a surprisingly large number of bat species (some of which are found
only here) and the evening traveller should ignore any old wives tales about
bats flying into your hair (increasingly, as the years pass, not a problem for
some of us anyway) and take the opportunity to watch the acrobatics as the
flying creatures leave their roosts to seek out a meal. For those from North America who are out at
night – there is one thing you do not have to worry about in Ireland when you
see a bat as rabies is not present in Irish mammals. (The country wants it to stay that way – this
is why it is so tough to get your dog through Irish customs).
Finally, in the area near Kilmore
Bridge you may note a few places where there appears to be paths or chutes worn
directly into the canal. These are
likely runs used by otters, one of the canal’s largest residents (clocking in
at over a meter in length, when the tail is added), and one that you’ll be most
happy to have spotted if you should get the chance. They are playful animals, but tough to see
other than at the times nearest darkness.
Ireland has a diminished but still fairly healthy population of these critters,
which have been hunted to extinction in a number of other European countries. Otters feed on fish (amongst other things) and
if you see a gnawed fish carcass along the canal this is likely a good
indication that they are about.
