‘Dear Harry…’ : An exhibition of a scientist lost to war

With support from the Heritage Lottery Fund, the University’s Museum of the History of Science is showcasing the life and work of Henry Moseley, a promising young scientist who lost his life in the First World War. Here, the co-curators of the exhibition highlight their favourite objects from the display.

Dr Elizabeth Bruton on the heliograph

‘One of the interesting things about communications in WWI is that you have modern and ancient technologies being used side by side,’ says Dr Elizabeth Bruton, co-curator of the exhibition ‘“Dear Harry...” – Henry Moseley, a Scientist Lost to War’ at Oxford’s Museum of the History of Science.

Henry ‘Harry’ Moseley was a signals officer with the Royal Engineers when he was killed at Gallipoli, Turkey in 1915. He was trained to use the most modern systems available at the time, such as wireless telegraphy for transmitting Morse code. Dr Bruton adds: ‘During WWI, radio telephony was also developed, and used in planes for artillery spotting and reconnaissance. By the end of the war, air-to-air wireless voice communication was possible over distances of up to ten miles. And the technology used for that was later used for broadcast radio and air traffic control.’

However, she continues: ‘Wireless communications were still relatively experimental at this time, and not particularly robust. The sets were big and heavy and required lots of people to carry them.’ Large acid batteries were the only source of power; to this day the Royal Engineers are nicknamed ‘scalybacks’ from the effects of the acid spilling from batteries they carried on their backs.

 Dr Elizabeth Bruton and the heliograph in the Harry Moseley exhibition. Photo by John Cairns

Because of these problems, signals officers such as Moseley also used older methods of communication including carrier pigeons and the heliograph, which sends signals by using a mirror to reflect sunlight. Dr Bruton observes: ‘There are descriptions of ancient Greeks and Persians using polished, reflective surfaces such as shields to signal using flashes of light. The heliograph, although developed in the early- to mid- nineteenth century, is very much based on those principles.’ Sunlight is reflected by the operator in the form of short and long flashes for sending Morse code.

Explaining why she has nominated it as her favourite object in the exhibition, Dr Bruton says: ‘I think the heliograph is a wonderful and indeed very beautiful piece of apparatus. I find it fascinating that WWI signallers were using a communications system based on 3,000 years of signalling history, alongside wireless telegraphy which was essentially only about 15–20 years old.

‘But also the heliograph is in many ways a better instrument for signalling, even though it’s much older. It doesn’t require any external power; it’s not difficult to set up; it does require trained operators, but has the advantage of being very portable, and incredibly secure – it’s almost impossible to intercept. It can also operate over short and long distances. While it was generally used over shorter distances in WWI, there are examples of it being used over distances of up to 80 miles in the Indian mountains in the late 19th century. It’s incredibly adaptable, rigorous and robust.’

Dr Stephen Johnston on the Moseley apparatus

Dr Stephen Johnston, Assistant Keeper of the Museum of the History of Science, has selected a rather unremarkable-looking piece of metal as his favourite object from the exhibition ‘“Dear Harry...” – Henry Moseley, a Scientist Lost to War’.

The item comes from what is known within the museum as simply ‘the Moseley apparatus’, commissioned by Henry Moseley in 1913 and used by him to make observations which provided a new basis for the periodic table of the elements.

Moseley studied the x-rays produced by a range of elements when electrons were fired at them. ‘Harry had to produce the x-rays in a vacuum,’ Dr Johnston explains, ‘so if you worked with each element one at a time, you would have to break the vacuum, get the old element out, put the new one in, seal it all up again, pump out the air – and every time you do that, you risk a breakage.’

This part of the apparatus sat inside the x-ray tube and consists of a rail with a trolley which could carry several different samples. Pulling the trolley by a string from outside the tube, Moseley could study a sequence of elements one after the other without breaking the vacuum.

 Dr Stephen Johnston with the Moseley apparatus on display; he makes a careful adjustment to the metal ‘trolley’. Photo by John Cairns

‘I chose this as my favourite object,’ says Dr Johnston, ‘partly because of the contrast between an unprepossessing piece of apparatus and the enormity of the work accomplished with it. But also because you get a sense of the force of Moseley’s personality – the young man in a hurry.

‘This is just an incredibly simple, almost childlike idea – essentially putting a miniature train set into a fragile and sophisticated research apparatus. It was utterly irrelevant to the physics of the experiment, and quite unnecessary, as long as you had plenty of time.

‘But Moseley thought he didn’t. Earlier he had been just days behind the Braggs, who had pipped him to the post with their work on x-rays and crystals, for which they would receive the Nobel Prize.

‘I think the lesson he learned from that was: don’t hang around – there are lots of other keen people out there in the world, and if you want to be ahead, get a move on!’

This individual apparatus was made in Manchester, commissioned at the end of 1913 when Moseley came back to Oxford after working with Ernest Rutherford. It arrived in Oxford at the beginning of 1914 – tragically close to the outbreak of war.

Harry Moseley had far less time than he knew.

Support the Museum of the History of Science