Less Tyring

I’ve now had my main bike for about 9 years.  Although there have been quite long spells when I’ve gone without cycling, we have clocked up quite a few miles by now so perhaps it’s unsurprising that the tyres were beginning to show serious signs of wear earlier this year, to the point that they needed replacing.

Last year, a friend of mine who is a keen biker (and bike mechanic) was clearing out his shed in preparation for moving away from the area and he gave me a couple of pairs of spare mountain bike tyres.  Both are classic off-road tyres – i.e. wide with deep treads (the sort of thing another friend refers to as “tractor tyres”).  They are great for riding on muddy off-road trails but not ideal for riding on the road.  They have quite a lot of rolling resistance (due to the large surface area in contact with the road) and tend to throw up quite a lot of spray in wet weather.  Apparently they are also less good for the road surface than tyres with less aggressive treads (I think it’s that rather than the width which makes the difference), although I’m sure that a single bike doesn’t make that much difference to the road in any case (and a few of our local roads are well overdue for resurfacing anyway).

Although these tyres are not ideal for the type of riding I mostly do (i.e. on-road), it seemed a shame not to use them when I needed to replace my tyres.  The original ones were probably about 2 inches wide with moderate treads and I certainly noticed the difference going up to 2.3″ tyres with heavy treads, mostly in terms of the added resistance (I didn’t particularly find these tyres to throw up more spray than the old ones).

The other day I decided to treat myself to a new set of tyres, and this time I’ve gone for Schwalbe Marathon, a brand and model that apparently have a very good reputation (as well as a really cool reflective stripe on the sidewall and some heavy-duty protective enhancements to reduce punctures and stuff).  The new tyres are 1.5″ wide, which is significantly narrower than my original tyres, to say nothing of the replacement pair, and they have a much less knobbly tread pattern (more like typical car tyres than tractor ones).

I fitted the new tyres on Saturday and it’s been quite windy ever since, which makes it difficult to draw a fair comparison, but the new tyres do certainly seem to make a difference.  I’ve been able to select higher gears for the same amount of pedalling effort, which translates to moving faster and indicates that less energy is being wasted.  On the downside, the narrower tyres (which are also run at somewhat higher pressure – about 90 psi instead of 60) are less effective as shock absorbers, so all the bumps in the road are much more noticeable.  As I mentioned before, some of the local roads are definitely in need of resurfacing!

I’m planning to keep the other tyres as they could come in handy if I want to do more serious off-road riding (for which the new ones would be less well suited) or to act as a temporary spare, should the need arise.


5.30591 Olympic swimming pools

It’s been a while since the last entry in my series on length measurements, so I thought it was about time for another.  Since I’ve been thinking about ancient Greece recently, it seemed appropriate to go for an ancient Greek unit of measure.  However, apart from one of a number of different cubit measures (which I’m planning to write about later), there were no  Greek units amongst the list of measurements that I prepared from the Google maps DMT when I first planned the series. Checking back with the DMT, it seems that this was because there weren’t any to choose from rather than just that I didn’t pick any for my list.

Employing a bit of lateral thinking, the closest I could come up with from my list was the Olympic swimming pool.  I suspect that if swimming featured in the ancient Olympic Games (it’s not mentioned in the Wikipedia article, but that doesn’t necessarily mean it was never contested) they didn’t use a standard size pool.  A swimming pool used for the modern Olympics, though, is supposed to have a standardised length of 50m.  It also has other details (such as width, water temperature, number of lanes and minimum depth) standardised according to the FINA specification, but it is the length (the greater of the two horizontal dimensions) that is used when an Olympic swimming pool features in Google’s DMT.  As far as I’m aware, it’s not a particularly common unit of length for measuring things other than swimming pools (the other common size of pool for competetive use being 25m, or half Olympic size).

As the title of this post indicates, the span of the Menai Suspension Bridge is about 5.3 Olympic swimming pools.  I suppose that means that swimming across the straits would be equivalent to doing 5 lengths of the pool (ignoring the added difficulties imposed by the strong currents and the distinctly sub-spec water temperature).  In any case, I think I’ll stick to cycling across the bridge rather than swimming under it.

I was interested to note that the Google DMT’s list of units didn’t include the σταδιον (stadion, plural: stadia; usually anglicised as stadium or stade), which is one of the better known ancient Greek distance units.  The problem could be that there is no single authoritative conversion factor from metres to stadia: although a stadion was defined as 600ft (according to Herodotus), there were several conflicting definitions of a foot in use at the time (dependent on geographical location) and hence a stadion in one place could be longer or shorter than one somewhere else.

Apparently the stadion unit was named after a running race over that distance, and the race in turn was named after the building in which it took place; as you might expect, this building also gave rise to the modern word “stadium” as a sports venue.  Wikipedia is slightly confusing as the stadion unit page says an Olympic stadion was about 176m, while the stadion race page says that the stadion race track at Olympia was about 190m long.  It could be that the stadion unit began life as the length of the race track and later standardised as 600ft and that the definition of a foot in use at Olympia was 1/600 of 176m, thus leaving the race track slightly longer than the new definition of a stadion.

Taking the definition of 1 stadion = 176m, the Menai Suspension Bridge measures about 1.5 stadia.  Using the length of the Olympic racetrack (1 stadion = 190m), it is about 1.4 stadia.

Bad breath

My recent foray into Euclid’s Elements has rekindled my interest in Ancient Greece, so I have decided the time has come to have another bash at learning Homeric Greek.  As well as being an interesting project in its own right, which will enable me to appreciate two of the classics of world literature (and, arguably, pillars of European culture) in their original language, I hope the exercise will enrich my understanding of Koine (aka. New Testament) Greek and provide a good doorway to other Greek dialects.

I already have some Homeric study material from a previous fling with the language, the main one being Clyde Pharr’s classic textbook Homeric Greek.

Working through some of the early exercises in the book this morning, I found a sentence which seems to demonstrate in quite an amusing way the range of variation possible in translating a sentence, due to the range of meanings of each word.

The sentence (lesson IV, no. 5) reads: καλη ἐστι θεα, ἐχει δε ψυχην κακην.

I don’t have a copy of the key to Pharr’s exercises, if such a thing exists, but I’m assuming the translation he had in mind was along the lines of the goddess is beautiful but she has an evil spirit (or perhaps an ugly spirit to contrast with her physical beauty).

However,   καλη can mean good, beautiful or several other things (all generally positive) while κακη is bad as well as ugly, evil etc. and ψυχη can be spirit, soul,breath or life. So there are several other possible translations for this sentence, including the goddess is good but she has bad breath.

Two phone-related observations to finish with:

I wrote the bulk of this post using the WordPress app on my phone, though I finished it on my PC (mainly to access the polytonic Greek keyboard, so I could put the breathings on the Greek sentence – I decided to leave out the accents though).  I notice that I seem to have written much shorter paragraphs than usual (indeed, several of them are just single sentences) and I wonder if this is largely due to the phone having a much smaller screen so a paragraph that is short on the computer screen looks quite long on there.  As you will probably have noticed, the current paragraph (which I’m writing on the PC) is just about the longest one in the whole post.

Yesterday I discovered what appears to be quite a promising app to help with my study of Homeric Greek.  It’s called Phlash Cards and is basically a set of flash cards designed to be used with Pharr’s textbook.   I’ve not made much use of it yet, but so far it seems to be working well.  It offers flashcards to test the vocabulary for each lesson (going Greek -> English or vice versa) as well as the paradigms for verbs, nouns etc. that are to be learned, and it has all the lines from the Iliad (all book 1, I think) that are introduced in the later lessons (as I recall from my previous outings with Pharr, the student is encouraged to memorise these).

Elementary, my dear

About 11 years ago, while I was studying for my PhD in abstract algebra (and, coincidentally, happened to have a friend who worked at a bookshop who was able to get me occasional books at a discount rate), I decided to treat myself to a copy of Euclid’s Elements, one of the classic texts of mathematics (with no discernible connection whatever to my official research topic).  This is a collection of 13 books covering not just plane and solid geometry (Euclidean, of course!) but also quite a bit of elementary number theory (although treated in a fairly geometrical way).

I went for the 3 volume Dover edition of Heath’s annotated translation of the complete 13 books, originally dating from about 1925.  After ploughing through the entire 150-page introduction, I must confess I didn’t get very far through my planned systematic study of the books themselves; in fact, the bookmark I found in there the other day indicates I got about as far as proposition 8 in book 1 (there being 48 propositions in that book alone)!

Recently I have been working through several of my old maths books, and scaring myself with the realisation of quite how much I’ve forgotten.   Euclid is the latest one to come down from the shelf and I’ve been enjoying working through some of the proofs in book 1 and glancing through some of the later books.  I’m not yet sure whether I’ll make another attempt at systematically working through the whole lot, though I expect I probably won’t get round to it any time soon.

Back among ὁι πολλοι

It’s getting on for a month since Iolanthe, which I was performing with the Rhos-on-Sea Savoyards in Colwyn Bay, finished and I’ve been intending to write something about how the shows went.

We had 4 performances, on consecutive evenings.  The house was comfortably full on the first three nights but surprisingly less full on the Saturday (which, being a weekend and the final night, would traditionally be expected to be the busiest night).  Although there were plenty of mistakes each evening (mostly different ones each time), things generally went pretty well.

One of the most memorable moments was when the Lord Chancellor missed one of his entrances on the first night.  The actor was sitting down in the dressing room revising his lines for the forthcoming scene and I was fairly sure that he was due on stage imminently.  Given that he’s got over 50 years experience as a Savoyard and I was new to the group, I was reluctant to say anything about this, but I mentioned it to one of the other established members of the troupe who gently raised it with him and was assured that there was plenty of time yet.  That was just a moment before the director came storming down the stairs to find out where the Chancellor was when he was supposed to be on stage!  The actress playing Iolanthe (whose last remark before his (intended) entrance was along the lines of “but, lo, here he comes…”) did a fine bit of ad-libbing (“I was sure I saw him coming. It must have been somebody else.”) and managed to keep the audience amused until he made it onto the stage.

I had friends go to see at least 3 of the performances and they all seem to have enjoyed what they saw, even on the Friday night, which was (for some reason) by far the weakest performance overall.  Several of them remarked how well I played the part of a pompous git – at least I hope they think I was only acting!

Sadly, the person who was giving me lifts across to the rehearsals has now landed a new job near Liverpool and will be moving away from the area very soon.  Since it’s a bit too far to cycle to Colwyn Bay every week and I don’t think it’s practical to get the train across every time, this means I won’t be performing in the next show (“The Mikado”, to be performed in the autumn) and quite probably not in any others.  I hope, though, that I might be able to get across and watch some more of the shows now that my experience of taking part in G&S has given me an increased appreciation for the art.

Space Watching

When I decided to get an android phone a few months ago, there were several reasons why I thought it would be a good idea (some of which I wrote about at the time).  However, there was one single app that tipped the balance from “I’d quite like to get an android phone sometime” to “I must have one NOW!!!”.  That was Google Sky Map.

As the name indicates, this is a planetarium app, i.e. one which provides a map of the night sky.  I’ve used several planetarium apps on various computers over the years, since first seeing one demonstrated in the early 1990s and then getting one for my Amiga a couple of years later.  However, what sets Google’s offering apart from the herd is that this one makes use of the position / location detection features on your phone to provide a map that updates in real time as you hold your phone up to the sky and move it round.  This makes it ideal for identifying stars, planets and other astronomical features that you can see (no more guessing whether it’s Venus or Jupiter that you’re looking at).  For those of us who live in cloudy climates, you can also identify where the astronomical features would be visible if the clouds weren’t obscuring them, and you can similarly locate them if hidden behind tall buildings, trees, or even the earth itself (i.e. you can always use it to find Uranus, no matter where you are).

It may not be one of the most practically useful apps on my phone, since I don’t generally find myself needing to navigate by the stars, but it’s certainly one of the most exciting (at least if, like me, you have some interest in astronomy).  It is an example of augmented reality, which until fairly recently was very much in the domain of science fiction.

Very thoughtfully, they have programmed Sky Map with a night viewing mode that renders the map in dull red on a black background and hence preserves your night vision (a moot point if you’re in an area with lots of street-lights, but potentially helpful if you manage to find a nice dark place for stargazing), as well as an ordinary mode that uses a full range of bright colours.  As well as being able to pan the map round the sky and identify what you’re looking at, you can search for a specific feature (by name or by browsing through an image gallery) and it will then give you pointers so that you can line up your phone and your eyes in the right direction to see it;  of course, it can’t do anything about the clouds or terrain features that may be in the way, but it sure beats panning madly round the sky in the hope of being able to spot when M62 shows up on the map.

I haven’t yet tried using Sky Map in conjunction with binoculars (or a telescope, not that I have access to one) for viewing and identifying features that are not visible to the naked eye, but it has enabled me to know what I’m looking at when I stand and gaze up at the night sky on clear nights, or know what I’m missing the other 90% of the time.


Still here

Evidently my initial momentum for posting on my new blog has pretty much dissipated by now, as it’s been almost a month since my last post!

As usual, I’ve been too busy living to worry much about blogging, but I have a few ideas for stuff to blog about in the next few days, so watch this space for more information.