h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

Entry: William Rowan Hamilton, Mathematician - A87757564
Author: Gnomon - U151503

An Irish mathematician famous for a flash of inspiration.

I think it's quite an achievement to write an account of quaternions in a way that a mathematical dunce like me can understand!

One or two questions:

You said that Hamilton reworked Newton's existing theory of dynamics 'inventing a large amount of mathematics'. I'm not sure whether this means 'developing a large number of new approaches to mathematics', or simply 'carrying out a large number of calculations'.

I wondered whether you needed to enlarge on the comparisons between quaternions and matrices, but I suspect this is a subject for another article.

I feel sorry for Hamilton looking for love - he sounds like a true !

I enjoyed this, too

I meant "He reworked Newton's existing theory of dynamics, developing many new approaches to mathematics to explain it", so I've reworded it as that.

Thanks.

Wow. What an Entry!

My 2 pence:

When you mention the bridge in the beginning, I immediately want to know where this is (being a geek myself). Is the carving still there?

I assume that the bridge IS indeed Broom Bridge... But later in the text a passage raises doubts:

"On 16 October, 1843, [...] he passed Brougham Bridge (nowadays known as Broom Bridge) [...] Hamilton was so overcome by the feeling of inspiration that, after noting his discovery in a notebook, he took out a pocket knife and scratched the following equation into the stone of the nearby bridge[...]."

When you state "nearby bridge" does it mean he PASSED Broom Bridge and then carved his equation into ANOTHER nearby bridge? Or is it the same bridge?

Then: Is Ms. Disney related at all to THE Disney (I mean Walt)?





Hell

Generally well written, interesting & should be entered into the guide. Here are a few minor quibbles / comments:

Early Life: “When William was 16 …. William lost all interest in the Classics from that time on and only thought of Mathematics”.
.......... This is surely wrong as stated … how would you go about proving this sweeping statement? On entry to University aged 18 he received a prize for his excellence in Hebrew suggesting he kept at least a passing interest in the classics (classical languages?). [Wikipedia says that Hamilton studied classics & mathematics at University]. So I suggest rephrasing to something less sweeping ... it provided a trigger for his later life long focus on mathematics or something.

Crystalline diffraction:
.......... Once accepted into the guide it would be illuminative to have a picture of biaxial refraction showing the conical pattern.

Hamiltonian Dynamics:
.......... It would be useful to give a rationale / some insight as to why Hamilton felt there was a need to reformulate the mechanics of Newton (as expressed in his time). You mention “people” could not see the need for such a mathematical treatment & the suggestion in this section is that it would have been a waste of time if quantum mechanics hadn’t come along nearly a hundred years later.
.......... I presume the mathematical reformulation had something to do with improving the versatility & applicability of Newton’s mechanics (switching from forces & masses to energy & momenta).

Quaternians:
.......... Once accepted into the guide it would be helpful to show a picture of Hamilton's "graffiti".

Life, Love and Lack of It: “At only 19, Hamilton met with a young woman, Catherine Disney, and they fell in love. … Hamilton never recovered from the loss of his loved one.”
.......... This seems a bit odd given, as you mention later, he considered marrying Ellen de Vere & did marry friend Helen Bayly & had children with her, suggesting there was a recovery of sorts. So I suggest replacing never with something less black & white.

Hmmm comments are like public buses in the UK ... wait ages then two come along together

Thanks for your comments, both. I'll have to look up the answers to some of them.

The carving was on Broom Bridge, not another bridge. I'll try and make that clearer. Unfortunately, it has worn away over the intervening 170 years and is no longer visible, but there is a plaque on the bridge commemorating the event.

Disney is not a very common name in Ireland - there are only 5 listed in today's phonebook. But Walt Disney seems to be descended from a family from Carlow, while Catherine Disney lived in Meath. I can't find any evidence that they were related.

I've made a few changes which I think address all the points raised:

1. Was Catherine Disney related to Walt Disney? - I've added a footnote saying that she does not appear to have been related.

2. "He lost all interest in the Classics..." - I've reworded this slightly and included Hamilton's own statement that he withdrew his attention and affection from the Classics.

3. "He never recovered from the loss of his loved one." While this is true, I haven't included the rather pathetic story of Hamilton's subsequent dealings with Disney, her attempted suicide and broken marriage, and his intimate correspondence with her. As a result it looks a bit out of place, so I've reworded it slightly and I hope that's enough.

4. Broom Bridge, or another nearby bridge? - I've reworded it to make it clear that it was Broom Bridge itself that he carved the equation on.

5. Is the inscription still there? I know state that it isn't but that there is a plaque commemorating the moment of inspiration.

I think that's everything.

Not quite. I still need to address the issue of Hamiltonian mechanics, which unfortunately I don't know much about.

More research needed.

Okay it seems that you were holding some bits back With regard Hamiltonian mechanics maybe you could say something along the lines that he reworked the mechanics of Newton into a more generalised and usable form such that it could more easily be applied to a wider range of problems ... and then you have the bit later that this Hamiltonian formulation was perfectly suited to & adopted into the quantum mechanics. As others have mentioned any further details would best be in a separate entry.

I've reworded that paragraph on Hamiltonian Dynamics slightly, in line with your comments, Stone Aart. Thanks for your help.

Ah, there is a great history of mathematics engraved in stone. Like Pi to 35 decimal places appearing on Ludolph van Ceulen's tombstone - http://www.ams.org/samplings/math-history/hap-6-pi.pdf

Great entry.

There was a sentence that made me stumble, though:

>>The mathematics course had recently been completely designed and was a very modern one with all the latest developments from France and Germany.

Do you mean it was a brand new subject for the college, or that the course was only partially designed previously, or that the course had been completely redesigned?


Geggs

>>The mathematics course had recently been completely designed and was a very modern one with all the latest developments from France and Germany. <<

Not knowing anything about this maybe something along the lines of "The mathematics course he took had only just been updated to include all the latest developments from the continent." may not have caused some to hover over the sentence. The inference was that the course allowed Hamilton to reach the frontiers of the subject fairly rapidly.

... but I see Geggs point regarding the use of the word "designed" which is placed in a sentence which generates a context suggesting the use of redesign would have been more appropriate.

That was a typo. I meant "redesigned. It's fixed now.

Geggs

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