Sir Alan Walsh [1916-1998]

Biography

Alan Walsh was born on 19 December 1916 and brought up in Hoddlesden, a small moorland village in the borough of Darwen, in Lancashire, England, about twenty miles north of Manchester. He was the eldest son of Thomas Haworth Walsh, who managed a small family cotton mill in Hoddlesden, and Betsy Alice Walsh (nee Robinson).

The family cotton mill, Vale Rock Mill, Holden Haworth Ltd, was one of two mills that employed most of the people in Hoddlesden and many from the next town. Alan’s father, Thomas, was an astute and remarkable man who managed the mill for 52 years, including the period during the late 1920s and 1930s when the cotton industry was badly hit by the depression. Thomas had the interests of his family at heart but laid down the rules and would not allow disobedience of any kind. Alan’s mother, Betsy, was a charming, warm-hearted woman. Alan was very like her in some ways but his astuteness and determination came from his father. The village was quiet: just one pub, a school, a church and a village shop, which Alan’s grandfather, Benjamin Walsh, ran and which sold everything from meat, vegetables and groceries to clothing. Benjamin was a friend and helper of the vicar, and had a big say in village affairs. Alan’s grandmother, Mary (nee Haworth), was a strong-minded woman of the old school who insisted on good manners at all times.

Alan’s uncle and godfather, Marsden Walsh, described Alan as a delightful and serious boy. He was something of a loner and happy with his own company, qualities his uncle said would stand him in good stead. Even though he had quite a serious side to him, he had a great sense of fun. He had what was known as a lazy eye and for a period had to wear a patch. He made light of this and fooled about so that his friends thought nothing of it because he made them laugh. He had a great sense of humour, but was never unkind at someone else’s expense. Whenever he talked about his early life, he would say he was brainwashed ‘ too much religious teaching ‘ and how narrow their life was. Once when asked what he wanted to do with his life he said I want to find things out and how they work

From the age of ten Alan attended the local grammar school in the nearby town of Darwen, where he passed the Northern Universities Matriculation examination in 1933 and the Higher School Certificate examination in 1935. Of his school days, Alan recalls:

I had no idea where I was headed during secondary school. In fact when I was 16 years old I was advised to do French, English and History and drop Science. At the time I was having trouble with eye strain and because I thought French, English and History would involve a lot of reading, I chose rather to study Mathematics, Chemistry and Physics in which I performed quite well. At that stage I was very uncertain about my next step. I remember being attracted by a teacher training course, but my headmaster had other ideas. He finally spoke to my father and they persuaded me to apply for the honours course in physics at the University of Manchester.

He received his BSc from the Physics School, Manchester University in 1937 where one of his early lecturers was Professor (later Sir) Lawrence Bragg, who was head of the University Physics Department. Alan recalled:

I had been at university only two weeks when I attended a lecture by Lawrence Bragg. In this lecture to the University Physical Society he told, in extremely simple language, the story of the pioneering work he and his father had done in their development of X-ray methods for determining the structure of crystals. The basic simplicity and beauty of their contribution greatly impressed us freshers: the drama was enhanced by the knowledge that their work had been of such outstanding merit that they were awarded the Nobel Prize.

In 1938, he began postgraduate research on the structure of ß-carotene in the Physics Department at the Manchester College of Technology, (which later became the University of Manchester Institute of Science and Technology). He spent one year at the Manchester College of Technology and then continued the theoretical work on the analysis of β-carotene for a further period after he had moved to the Physics section of the British Non-Ferrous Metals Research Association in 1939. Of this time at BNF Alan recalled:

In the first place I was to work on the development and application of spectroscopic (emission) methods of metallurgical analysis, about which I virtually knew nothing, but with the intention of also, in due course, working on X-ray studies of metals. With the outbreak of war (on the day he was due to start), these plans were abandoned and for the duration I worked only on spectroscopy.

During World War II, Alan was unable to join the Services because of his metallurgical occupation, but he undertook part-time service in the Home Guard, where ‘he was put in the mobile cavalry (bicycle section), being of the athletic type. He had represented Manchester at tennis’.

Alan Walsh was awarded the degree of MSc (Tech) in 1944 for a thesis entitled ‘An X-ray examination of ß-carotene’. In 1960, he was awarded a DSc from the University of Manchester for his contributions to atomic and molecular spectroscopy.

At CSIRO

He was appointed to the CSIR Division of Industrial Chemistry, Melbourne, in 1946 but before leaving England, it was arranged for him to spend a period of three to four months in the laboratory of GBBM (later Sir Gordon) Sutherland in Cambridge, obtaining experience in the new field of infrared molecular spectroscopy. During this period in Cambridge, Alan established life-long associations with two molecular spectroscopists, Donald Ramsay and Norman Sheppard, the latter of whom introduced Alan to the experimental and theoretical aspects of infrared spectroscopy. This work in Sutherland’s group led to a paper in Nature on the infrared spectrum and molecular structure of phthiocerane. In a letter to Ian Wark, Sutherland wrote in my opinion you have got hold of a very good man

Alan set sail for Australia via the USA, where he visited a number of companies and laboratories to see the various items of spectroscopic equipment that Lloyd Rees had ordered for the new spectroscopy laboratory at CSIR and arrived in Melbourne in April 1947.

Research interests

In the period 1947-51, Alan worked on infrared molecular absorption spectroscopy and atomic emission spectroscopy before switching to atomic absorption spectroscopy for the rest of his career at CSIRO. He retired from CSIRO in 1977.

Infrared molecular absorption spectroscopy

Upon commencing at CSIR Alan set about installing the new Perkin-Elmer Model 12B spectrometer, thereby establishing his first interaction with the Perkin-Elmer Corporation. This was the first operating infrared spectrometer in Australia, and there was a steady stream of requests for service and collaborative work from organic chemists both within the Division and outside it. Alan was particularly interested in understanding the mechanics of the technique and studying the structure of small molecules. Together with Arthur Pulford, an MSc student from the University of Sydney, he studied the vibrational spectrum of nitrosyl chloride (NOCl) and calculated its geometry and thermodynamic properties.

The Perkin-Elmer Model 12B, like all commercial infrared spectrometers at that time, used a direct current (DC) amplification system. To obtain good spectra with such systems was difficult because small changes in ambient temperature caused pronounced wandering of the baseline. Alan recalled :

The best spectra were obtained late at night or in the early hours of the morning. It was therefore a memorable occasion, which substantially improved my quality of life, when our Model 12B was converted to a Model 12C. This incorporated a fast thermocouple, which permitted the use of a modulated light source and a synchronous AC [alternating current] detection system and completely removed the problem of drifting base lines. Recording infrared spectra was transformed from a chore to a pleasure.

Alan soon realised that the resolution of the Perkin-Elmer (prism-based) spectrometer was quite inadequate for resolving the rotational lines of any but the lightest molecules, and even in these cases the full details of the spectrum were not revealed. To improve the resolution he devised a simple and elegant modification of the infrared prism monochromator in which radiation was passed two or more times through the same optical system. To do this he placed a pair of right-angle mirrors at the exit slit of the spectrometer to reflect the radiation back through the prism and, to isolate the desired multiple-pass beam from the other beams, he placed a rotating ‘chopper’ in front of the additional mirrors to modulate only the multiple-pass light and fed the output of the thermocouple detector to an amplifier tuned to the frequency of the chopper. An additional advantage of this modification was that the level of stray light, hitherto a major problem in infrared spectroscopy, was reduced dramatically.

Alan’s ‘double-pass monochromator’ was patented in 1950, with coverage in Australia and eight overseas countries. Perkin-Elmer, the world’s major manufacturer of infrared spectrometers, secured an exclusive licence and in 1953 began manufacturing a kit of ‘Walsh Mirrors’ to allow the conversion of their standard infrared spectrometer to a double-pass monochromator system. This experience with patenting and licensing and the interaction with Perkin-Elmer had significance for future events in that it involved Alan personally with the commercial aspects of scientific investigation.

Atomic emission spectroscopy

Shortly after his arrival at CSIR Alan also initiated a project to investigate the fundamental processes occurring in spectroscopic atomic-emission sources, and in particular to attempt to correlate the emission of radiation from the discharge with the electrical phenomena occurring in circuits containing an arc or a spark gap. He had the instrument workshop construct a source unit to the Walsh BNF design, which was capable of producing sparks that were electrically identical. Although such source units were by then well established in laboratories in the UK, the CSIR unit proved rather unreliable and was not sufficiently stable for the research Alan was proposing. John Shelton, who worked with Alan on this project, writes:

It is interesting to speculate whether Walsh would have invented atomic absorption analysis if the source unit had been successful and allowed the planned research on inter-element effects to proceed. The frustration of the planned emission work stimulated him to think more and more about the tremendous number of sample atoms in the ground state, compared with the few, sensitive to minor changes in electrical and other conditions, in excited states.

Atomic absorption spectroscopy (1952-77)

Details of Alan Walsh’s outstanding research in atomic absorption can be found in Peter Hannaford’s 2000 memoir of Alan Walsh (available by following the link in the Sources below) and the CSIROpedia entry Atomic absorption spectroscopy.

Retirement from CSIRO

Alan Walsh retired from CSIRO on 5 January 1977, just after his sixtieth birthday and after thirty years of service and fifteen years as Assistant Chief of the Division of Chemical Physics. He had for many years said I will have run out of new ideas by the age of sixty and I should make way for a younger person

Two weeks after giving notice, Alan received a telex:

I have pleasure in informing you that Her Majesty The Queen has been graciously pleased to approve the recommendation that you be awarded a Royal Medal in recognition of your distinguished contributions to emission and infrared spectroscopy and your origination of the atomic absorption method of quantitative analysis.

Alan had the distinction of being only the fourth Australian scientist to have been awarded a Royal Medal, after Ferdinand von Mueller in 1888 and Nobel Laureates Sir Macfarlane Burnet and Sir John Eccles. In the Silver Jubilee Queen’s Birthday Honours List in June 1977, Alan was created a Knight Bachelor for ‘his distinguished service to science’. Alan’s many other honours included election to Fellowship of the Royal Society of London in 1969 and Foreign Member of the Royal Swedish Academy of Sciences in 1969, being only the second Australian scientist (after Burnet) on whom the latter honour had been bestowed.

On the occasion of Alan’s retirement, his Chief of Division, Dr Lloyd Rees, paid the following tribute:

Alan Walsh did not only invent an analytical instrument called the atomic absorption spectrophotometer ‘ he created a field of scientific work in atomic absorption spectroscopy and initiated and cultivated its application to elemental chemical analysis in areas as disparate as agriculture and chemical industry, and medicine and the mining and metallurgical industries. His contribution to science, industry and human welfare has been enormous. In spite of his great distinction Alan Walsh is a human being ‘ he enjoys life and has never found it necessary to develop eccentricities or affectations.

He died in Melbourne on 3 August 1998, aged 81.

Honours and awards

For his outstanding contributions to science Alan Walsh received many honours including:

Fellowships

Awards

Honorary degrees

Special journal issues

Sources

• Hannaford P, 2000, Biographical memoirs: Alan Walsh 1916-1998 (Australian Academy of Science)
•  The Alan Walsh Medal for Service to Industry

Related information

• http://www.eoas.info/biogs/P000860b.htm