A curious poem

Recently, a friend of mine in India came across a strange poem originally published in the Journal of Chemical Education in 1925, having noted that it seemed to have some relevance to crystals and, in particular, to the name Moseley. This immediately struck me as interesting, especially as Moseley's name has a special connection with Trinity College at the University of Oxford and the Clarendon Laboratory, UK. So who was this chap, Moseley?

Well, he was Henry Gwyn Jeffreys Moseley, known usually as Harry Moseley. And his claim to fame, especially in the field of crystallography, was indeed profound. He graduated from Oxford in 1910, spent some time in Manchester with Ernest Rutherford and then returned to Oxford to carry out his research in 1913.

Now, it is important to recall that, at the beginning of the 20th century, one of the outstanding questions that needed settling had to do with the nature of X-rays (originally discovered in 1895 by Wilhelm Roentgen). The burning question for physicists then was: are X-rays particles or are they waves? Most scientists believed the wave theory, but some, including William Henry Bragg (WHB), thought they consisted of neutral particles. Then, in April 1912, an important experiment was carried out at the suggestion of Max Laue, a Privatdozent at the Institute of Theoretical Physics in Munich, but without the agreement of Arnold Sommerfeld, the head of the institute. The actual experiment was carried out in secret¹ one night by Walter Friedrich, an assistant of Sommerfeld, and Paul Knipping, a student of Roentgen. The experiment consisted of shining a beam of X-rays onto a crystal and then recording the scattering of the X-rays on photographic film. After several failed attempts, they finally obtained photographs that indicated that the X-rays were deviated by the crystal and even formed sharp spots on the film. This seemed to demonstrate that the X-rays had been diffracted by the atoms in the crystal, thus proving that X-rays were wave-like. Laue, later ennobled as von Laue, received the Nobel Prize in Physics in 1914. Although Friedrich and Knipping did not share the prize, Laue divided up the prize money between them. You can read Laue's amusing account of the experiment here.

In the summer of 1912, word of this important experiment reached WHB, then Professor of Physics at the University of Leeds. He then set about trying to show that he could explain the effect with his particle theory. His son, William Lawrence Bragg (WLB), had just graduated from Cambridge University, and he joined his father in conducting experiments to demonstrate the viability of the particle theory. The experiments all failed, but in August that year, WLB, while back in Cambridge, suddenly realised that Laue's results actually supported wave theory rather than his father's corpuscular theory.² WLB's theory was remarkably simple as it drew upon well known theories of the reflection and scattering of light.

From this, WLB produced the equation that later, after modification, became known as Bragg's law. This took the form of a cosine function, where the angle q referred to the angle of incidence of X-rays on planes of atoms in the crystal. In this formula, l is the X-ray wavelength and d is the distance between the planes. Whenever this equation was satisfied for all three terms l, d and q simultaneously, the scattered X-ray left a spot on the film. WLB was able to show that it was possible to use this to derive information about the structures of crystals, and that he could explain all the spots seen on the Laue diagrams as arising from diffracted X-rays with different wavelengths and from different planes within the crystal. He wrote a paper on this discovery that was read by J. J. Thomson on 11 November 1912 at the Cambridge Philosophical Society. Following this, he worked closely with his father to show how to solve crystal structures in numerous materials throughout 1913 and 1914 until all research was interrupted by the First World War. In 1913, WLB made use both of Laue's film method and of WHB's recently developed ionization spectrometer. The spectrometer gave more precise measurements than the film method (by the way, WHB's ionization spectrometer can be seen as the forerunner of the automatic diffractometers universally used today in crystallographic research). I suggest that it was the use of WHB's spectrometer that led in 1913 to changing Bragg's formula to the more familiar sinusoidal function that we use now

λ = 2dsinθ.

This is because it is more natural when using a spectrometer to measure angles from the incident beam direction, thus 90° minus WLB's original angle q. Both father and son shared the 1915 Nobel Prize in Physics during the war.

Now, this is where Harry Moseley comes into the story. At the time, Harry was working in Manchester under Rutherford and one day gave a talk to explain the Laue experiment.

WHB was present at the talk and afterwards told Harry that his son, WLB, had also developed similar ideas. However, as far as I know, Harry's talk was not recorded, so we do not know if he had been able to gain as much insight as WLB. Harry later said that he was confused by crystal structures and that WLB had gone further. WHB was initially more interested in studying the characteristics of X-rays rather than pursuing crystallography, but after a difficult discussion with Rutherford, he reluctantly agreed to leave this field to Moseley and, instead, to concentrate on crystallographic research. WHB then magnanimously offered to help Moseley by explaining the tricks he had developed from his experience in using the spectrometer. At the time, it was not known for sure what the wavelength distribution of X-rays was and that it contained both a broad white component (a continuum of wavelengths) and sharp characteristic lines. In using the spectrometer, it was essential to change the detector angles through very fine steps to avoid missing the sharp lines. Moseley was able to measure the frequencies of the characteristic lines of X-rays for a number of elements, discovering that the square root of the frequency was proportional to the atomic number (the number of protons in the atom). If you ever visit Oxford, you can see his original diagram in the Clarendon Laboratory. This discovery was important because it established the importance of the atomic number and supported the concept of the periodic table, earlier proposed by Dmitri Ivanovich Mendeleev in Russia. It also enabled Harry to fill in some of the gaps in the list of elements in the then known periodic table (see the gaps at atomic numbers 43, 61 and 75).

   

Moseley had a prestigious talent and was almost certainly destined for a Nobel Prize. However, with the outbreak of the world war in 1914, research ended. Harry decided to show his patriotic duty by enlisting in the army, despite entreaties against this by his family. Calamity struck on the morning of 10 August 1915 during the botched battle of Gallipoli when 30,000 Turks, 'calling upon the name of God', streamed down a hill towards the British lines. According to General Sir Ian Hamilton:

…our men stood to it, and maintained, by many a deed of daring, the old traditions of their race. There was no flinching. They died in their ranks where they stood.³

Thus ended the life of a promising young man.

Coincidentally, WHB's other son, Robert, was also wounded at Gallipoli on 1 September 1915 and died from his wounds the next day. The effect on WHB and his wife was devastating, something neither of them ever overcame. After the war, in 1920, WHB and WLB were invited to Stockholm for the Nobel Prize ceremony. But WHB refused to go because "there will be Germans there!" His son also did not attend, presumably because of his father's influence, but he did go in 1922.

So, finally, we now come to the poem. Here it is.

Ballad of Ryerson

Reprinted with permission from Edwin H. Lewis (1925). J. Chem. Educ. 2, 610. Copyright 1925 American Chemical Society.

Lo, Paris and Cambridge and Ryerson were needed to make one thought

Till on the final droplet-star, the massiest, tiniest sphere,

The moon-grain lingered a moment and told the secret here.

Now take the charge and the crystal! Young heroes, unlock the lead,

And kindle a rose for mother ere the rose of her hearth be dead.

O planet, ridged with Calvaries and rimmed with Suvla Bays,⁴

Not all your nights are reined with fire, not all of your lightning slays,

Then why have you slain your darlings? And why did your heart disclose

Fury and flame and the flash of lead when your dearest brought you a rose?

Ah, the rose! The expectancy and the rose!

The beat of the harp is broken, the heart of the gleeman is fain

To call him back from the grave and rebuild the shattered brain

Of Moseley dead in the trenches, Harry Moseley dead by the sea,

Balder slain by the blindman there in Gallipoli.

No longer the towers of Oxford whisper the middle age,

But the dearest of hopes destroyed and the great unwritten page.

No longer the Trinity meadows bloom as in other days

But the sunlight dreams of violets beyond the violet rays.

Beyond the violet seek him, for there in the dark he dwells,

Holding the crystal lattice to cast the shadow that tells

How the heart of the atom thickens, ready to burst into flower,

Loosing the bands of Orion with heavenly heat and power.

He numbers the charge on the center for each of the elements

That we named for gods and demons, colors and tastes and scents,

And he hears the hum of the lead that burned through his brain like fire

Change to the hum of an engine, the song of the sun-grain choir,

As it spins the chaliced lightning to banish shadow and shade,

Or drives the heavy hammers by the sun-grain cannonade,

Or wears the wings of the humming birds that flash through heaven afar,

Or grinds the golden barley by the voltage of a star.

Now, if they slay the dreamers and the riches the dreamers gave,

They shall get them back to the benches and be as the galley slaves.

So, what are we to make of this? The author appears to be Edwin Herbert Lewis (1886–1939), a rhetorician, novelist, poet and professor of English at the Lewis Institute of Chicago. It seems to me that the poem is a lament for a promising life cut short, for it was written 10 years after Moseley's death. Why Lewis wrote it, I don’t know, but I assume the 10th anniversary of the loss of Moseley must have been keenly felt by many at the time. And why the name Ryerson? There is a Ryerson Laboratory in the Physics Department at the University of Chicago, but what is the connection with Moseley?

 

I see that in his book White Lightning, published in 1923, Moseley is mentioned thus:

And it was in Jimmy’s house in June of 1914 that Marvin picked up the Phil. Mag. and read the most important article he had ever read in his life. The author was quite unknown to him – one of Rutherford’s men who signed himself H. G. J. Moseley. This man was reporting some measurements that he had made by the use of crystal gratings and short rays. He asserted that the method gave a spectrum of two dark lines for each element, and that the frequency of vibration increased definitely, step by step.

Marvin laid down the magazine and reflected. This unknown Moseley had found it – a sure way to determine the amount of electricity concealed in the heart of any atom. In ten years chemistry would be a new science. In much less than that time every chemical element would receive a number indicating the charge on the nucleus.

Moseley had already numbered some thirty elements, beginning with aluminum as 13, and calculating gold at 79.

 

So, if anyone out there can fill in more details and throw more light on the reasons for this poem, please let me know.

Addendum: Many years ago (as mentioned in my Editorial), I went into the office of one of our secretaries and noticed a cardboard box in the corner behind the door. I also saw that every time someone entered the room, the door was slammed against the box. I looked inside the box, and there was one of Moseley’s original X-ray tubes, very similar to the one seen being held by Moseley in the image at the beginning of this article. Miraculously, despite its fragility, it had survived despite its rough treatment. It can now be seen in the small museum of the Clarendon Laboratory.

Notes