Meet Skyclock:

Twilight awareness – the gift of time.
Skyclock is twilight, sunrise, and sunset times on an analog face for your exact location.

Skyclock, for both the iPhone and the PC (Windows only), has a 24 hour mode that makes a lot more sense to me than the 12 hour ‘conventional’ mode.

Skyclock for iPhone

Skyclock for iPhone

Find the iPhone on the iTunes App Store (it’s free, ad-supported) and go to Skyclock for the PC version.

I feel it’s similar to the more minimal Sol for the iPhone, but sadly that seems to have disappeared from the App store.


The Willis World Clock

This is the Willis World Clock in the London Science Museum.


I’ve not found out much about it, or who Willis was, but I did find a reference to a smaller versionin a 1939 copy of Flight magazine (here) and I presume the description is mostly valid for this version too:

The operation of this clock is extremely simple, with a twenty-four-hour moving disc in the centre and a separate minute hand below. The main face of the clock is laid out in sectors, with the names of all the more important countries and cities in the world indicated by arrows, and the time for each particular place is merely read cif against the appropriate arrow. The timing disc itself is clearly marked in a.m. and p.m. sections, so that, even when the twenty-four method of reading is not being used, there is no possibility of error. Those countries and cities where “summer time” arrangements are in force are printed separately in red type. For example, Great Britain and France have two positions, one at Greenwich time and one, for the summer season, on the mid-European time arrow.

Needless to say, such a clock will be useful in working out E.T.A.s which are likely to be at or near nightfall, and also for timing the reception of both weather broadcasts and others required for D/F bearings. The world clock is obtainable from J. H. Willis and Company, Ipswich Road, Norwich, and the aircraft or small marine type, for instrument-board mounting, is priced at 137s. 0d.

One of these – non-functioning, I think – was sold on eBay recently. You could have bought it for just £13.

More iPhone clocks and watches

A few more 24 hour iPhone applications are appearing in the iTunes App Store. If you want to check any of these out, let me know how they work – I have no idea.

Here’s a familiar sight: the famous Shepherd Gate Clock at Greenwich, London. The Shepherd Gate Clock (this link is a link to the App Store) costs a modest dollar. I’m assuming that this is a genuine 24 hour analog clock. The time here is 20:10. It’s going to look a bit odd at midnight, with that sunlit brick wall…


This next one is a puzzle. It’s called iWatch, and it features an attractive rendering of three watches, including this Patek Phillippe watch with a 24 hour rotating dial. What looks like the hour hand is really the minute hand, and what looks like the minute hand is really the second hand. So the time on this picture is about 04:18:49.


(I’m not a big fan of the design, to be honest. The map is coarse, and that font isn’t attractive.) The real puzzle, though, is why this app is suddenly no longer available on the App Store, now that I want to provide a link to it.

The next app, nHands Clock, is a useful clock that lets you add as many hours hands as you like, with colour and labels of your choice. It’s a clever way of showing you the different time zones of people you know:


Finally, this excellent app is called 25h:


The idea is simple:

Feeling overstretched? 24 hours in a day is not enough? Then 25h is a clock for you.

Trick yourself into having 25 hours in a day. Get things done faster and have an extra “hour” for yourself.

Note that 25h does not modify time–space continuum (or your biological clock) to give you an extra hour. It simply makes the rest of your hours appear a little shorter so that enough time is saved for an additional shorter “hour” at the end of the day.

I know some people who set their watches fast – this is an interesting alternative.

How to grow clocks

I stumbled across an interesting piece on YouTube recently. It has only a passing relevance to this site, but it was too cool to ignore. It’s from a contributor called cdk007, whose presentation is part video, part lecture, and part software demonstration. It explores an idea that was made famous by the Reverend William Paley, an 19th century English clergyman, who argued that, just as watches are too complicated to have arisen spontaneously and must have been fabricated by a watchmaker, so life on earth must have been made by an intelligent designer. The ‘blind watchmaker’ analogy has been explored both by evolutionists as an example of an illogical and fallacious argument in favour of some god-like creator figure, and by creationists as a – perhaps initially – plausible objection to evolution. Most famously, Richard Dawkins has persuasively argued the Darwinian side, pointing out, in his ‘Blind Watchmaker’, that the forces of natural selection can produce amazing complexity.

cdk007 isn’t content to just point out the illogicalities of the creationist argument, though. He goes one step further, and examines the argument using a software simulation. I love the way his collection of mating clocks with mutating genomes manage to enter ‘the age of pendulums’, before evolving further into four-handed clocks.


The clocks grown by the simulation manage to evolve – you guessed – a 24 hour dial! Notice here the number of seconds on the left-most dial – 86,817 is close to the number of seconds in a 24 hour day.


The video can be seen here.

Linear thinking

Recently I think there have been a few more different ways of showing time. Here’s a picture of the clock-setting interface on an iPhone:


The illusion of a circular wheel rotating is very strong, particularly when you flick it up and down with your finger – it speeds up and slows down like a well-oiled bicycle wheel. But the display is effectively a digital clock that’s also a linear analog clock.

Measuring time as a point along a line is probably as old as angular time measurement, if not older. Early sundials from Egypt show the length of the sun’s shadow being measured on a simple graduated stick, although angular displays are also common in the ancient world. Through history the passage of time has also been marked by a change of water level, a decrease in height of a marked candle, or a change in length of a trail of slow burning incense.

A striking linear clock can be seen in Picadilly Circus tube station in London. A metal band travels from east to west over a fixed Mercator map of the world, showing the mean solar time for any location. The band itself is a 24 hour indicator, but if you think about it, it’s clear it has to be 48 hours long (since it has to go round the back of the map).


There are a number of software linear clocks around. Here’s an old one called Stripclock that I used to run on my Palm. (You can google for this but there’s no current url for the author, who might be called Fraser McCrossan) This was great because by tapping you could zoom in closer and closer onto the time display – either watch the seconds speed by or follow the imperceptible movement of the week or month.


And here’s a more recent Flash version of the idea. Not zoomable, but compelling in a different way:


(The live Flash version is at Unlike the iPhone controls, you don’t get the sense of any circularity in time. To the left – if you could scroll back far enough – is the formation of the universe; to the right, the heat death of the solar system…

Notice that this style of display has exactly the same ‘problem’ as circular analog clocks: it’s hard to show the various time units to any proportional scale. A second is as big as a minute, although they move to the left much faster. This is a great picture of time flowing like water under a bridge.

The world as seen from Paris in 1800

In the Musée des arts et métiers in Paris you can see this clock, a Cadran Universel made by Janvier in 1800:


This has a fixed outer dial containing a series of towns and cities around the world, arranged according to their longitude. Paris is at the top at 0 degrees (and London has been squeezed in as small as possible just above it and to the right, not yet at 0 degrees longitude!).

This circular list of geographic locations gives an intriguing picture of the world as seen from Paris in 1800. I’ve put together a quick list of a few of the places mentioned, with the Paris-based and my estimates of the London-based longitudes, to see how many can be identified:


7.5 (5.5) Gibraltar ESPA – Gibraltar
15.0 (13.0) I Lancerote Can. – Lanzarote
22.5 (20.5) Hola ISLANDE – ?
30.0 (28.0) Thule T’AUST – Thule Islan (Morrell Island) in South Sandwich Islands
37.5 (35.5) Olinde Bresil – Olinda, Brazil
45.0 (43.0) Rio Janeiro Br
52.5 (50.5) Para ?? AM.
60.0 (58.0) I Burgeo – Bridgetown, Barbados
67.5 (65.5) C de la Reselution
75.0 (73.0) La Conception A M
82.5 (80.5) Fanal & Savanna
90.0 (88.0) N Orleans
97.5 (95.5) Vera-Cruz
105.0 (103.0) Zacalula ? Tamazula in Mexico?
112.5 (110.5) S Joseph CALIF – San Jose ?
120.0 (118.0) I. S. Paul
127.5 (125.5) C. Flatterie – Cape Flatterie, near Seattle
135.0 (133.0) I Pitcairn – Pitcairn Island
142.5 (140.5) I Cumberland
150.0 (148.0) I Milea . Ounab
157.5 (155.5) ? – obscured by the hands
165.0 (163.0) ? – obscured by the hands
172.5 (170.5) I de Navigateurs

Conspicuous by their absence are most of the major US cities. In 1800, these were either unimportant or deliberately ignored, apart from New Orleans and Savannah.