As an astronomer, he is best known for his work in determining the distance from the Sun to the Earth (the
astronomical unit) from 1900 to 1909: for this achievement, he was awarded the
Gold Medal of the
Royal Astronomical Society and was elected a fellow of the
Royal Society.[1] His later professional career was in
surveying and
cartography, an extension of his astronomical interests.
Although Hinks had originally intended to measure stellar parallax, and produced an ambitious plan to do so in conjunction with
Henry Norris Russell,[5][6] an even more fundamental opportunity arose with the discovery in 1898 of
433 Eros. It soon became apparent that Eros was a
near-Earth asteroid, and would be passing very close to the Earth in late 1900 – early 1901. The closest approach was about 30 million miles (48 million kilometres), or about 125 times the distance from the Earth to the Moon, a stone's-throw in astronomical terms. With Eros passing so close to the Earth, it would be possible to measure its
parallax to high precision, and so calculate the
solar parallax or, in other terms, the distance from the Sun to the Earth (now known as the
astronomical unit, a name that was coined at about this time).[7]
An international effort to obtain accurate observations of Eros was put in place under the co-ordination of
Maurice Loewy, then director of the
Paris Observatory. Hinks was an enthusiastic, even zealous member of the team from the start,[8] and was responsible for the observations from
Cambridge Observatory. In total, no fewer than fifty-eight observatories were involved.[5] Hinks spent three months observing Eros from dusk until dawn in 1900/01 – or rather, trying to observe Eros: the weather in Cambridge was unusually wet that winter, and Hinks only had half a dozen cloud-free nights during the whole period.[9][note 1] Fortunately he was using a photographic telescope, and was able to obtain some 500 exposures, as results from more traditional visual methods (meridian line or micrometre measurements) would have been far less conclusive.[5]
Hinks published the Cambridge results in November 1901,[10] but this was far from the end of the task. The results from all the participating observatories had to be collated and analysed, a monumental feat which initially fell to Loewy in Paris. An additional problem was that it was not clear how the different
measurement uncertainties should be treated, especially as different observatories used different methods to calculate the apparent position of Eros. Hinks also participated in this initial period, publishing a comparison of his Cambridge results with those from the
Lick Observatory on
Mount Hamilton, California, and from the
Goodsell Observatory near
Minneapolis, Minnesota.[11] However Hinks became increasingly concerned about the
systematic errors in several of the results,[12] and published his own provisional result for the solar parallax in 1904, based on photographic observations from nine observatories.[13]
Hinks continued to work on the problem as secretary of the
Royal Astronomical Society, a post he held from 1903 to 1913 – he admitted himself that solar parallax work took up most of his time at the Cambridge Observatory,[14] although he did publish other papers. When Loewy died suddenly in 1907 (aged 74), Hinks appears to have taken over the final reduction of the data. The final result was published in 1909:[14] the solar parallax was 8.807 ± 0.0027 arcseconds, slightly larger than the 8.80 arcseconds that
Newcomb had calculated and that had been internationally accepted since 1896.
Measurement of the lunar mass
A bonus result was that Hinks was also able to calculate the ratio between the mass of the Earth and the mass of the Moon as 81.53 ± 0.047.[15]
Later work
Hinks resigned from the Cambridge Observatory in 1914 when he was passed over for the directorship in favour of the younger
Arthur Eddington (1882–1944), a brilliant mathematician and one of the earliest
astrophysicists. Hinks complained
"the whole trend in policy in Cambridge & England generally […] is to take astronomical posts as sustenance for mathematicians. […] They must have been mad to imagine that a man who had the ambition to do what I had been able to do would be content with an inferior position and no fun all his life."[16]
"Now that Peace is in sight, I find my thoughts reverting to astronomy a little, and I hope eventually to finish off some things I had to leave incomplete in 1913. […] The statistical stuff with its integral equations was bad enough. But relativity is much further beyond the limits of my comprehension, and I shall find when I start to make up my two years arrears of reading that I am hopelessly outclassed."[17]
Geographical career
In 1903, Hinks undertook a course in
surveying at the
School of Military Engineering in
Chatham in Kent.[18] At the time, there was no
National Service (
conscription) in the United Kingdom, and it is possible that he did the course to gain a profession to support his young family (he had been married for four years, and his son Roger was born in 1903), after eight years in a poorly paid junior post in astronomy. The same year, he was promoted to senior assistant at the
Cambridge Observatory and appointed secretary of the
Royal Astronomical Society.
Hinks was involved in the organisation of the expeditions to observe the total
solar eclipse in May 1919 from
Príncipe off the west coast of Africa and from
Sobral in Brazil,[21] during which his nemesis from Cambridge,
Eddington, would provide one of the first proofs of
Einstein's theory of
general relativity.
Hink's most controversial role was as joint secretary of the
Mount Everest Committee,[22] a joint body of the RGS and the
Alpine Club dedicated to organising an ascent of the world's highest mountain. The initial
1921 British Mount Everest reconnaissance expedition suggested a route to the top from the
Tibetan side, and a
second expedition was sent out in 1922 to try to reach the summit. The 1922 expedition never made it to the summit, despite three attempts and, on the second attempt led by
George Mallory, an avalanche killed seven
sherpas. However
George Finch and
Capt.Geoffrey Bruce set a new altitude record, climbing to 8326 metres (27,316 feet) on the second summit attempt.
Another expedition was organised for 1924. However Hinks vetoed Finch's inclusion on the expedition, despite his altitude record during the 1922 expedition, ostensibly because he was divorced and had accepted money for lectures. The true reason was that Finch was Australian, and Hinks was determined that the first person to reach the summit should be British. Mallory (who had also given paid lectures about the 1922 expedition) initially refused to return to Everest without Finch, but was eventually persuaded by members of the
British royal family, at Hinks' request.[23] Mallory and
Andrew Irvine died during the third attempt on the summit, ending all attempts to climb Mount Everest for several years.[24]
Hinks published two textbooks on
cartography and surveying, Map Projections (1912) and Maps and Survey (1913). After the war, he was involved in the development of
radiotime signals[25] and in
geodesy in general,[26] two interests that are very much linked with astronomy.[1]
^Despite the reputation of the British weather,
Cambridge, in the east of the country, has a relatively dry climate: the average rainfall (552 mm, 21.7″ annually) is the same as that in
Netanya in Israel, for example… Source:
WorldClimate.com.
^Marsden, Brian G. (1965), "Measurement of the Astronomical Unit", Astronomical Society of the Pacific Leaflets, 9 (427): 209–16,
Bibcode:
1965ASPL....9..209M.
^Blakeney, T. S. (1970). "A. R. Hinks and the First Everest Expedition 1921". The Geographical Journal. 136 (3): 333–343.
doi:
10.2307/1795183.
JSTOR1795183.
^"Treachery at the top of the World", The Advertiser, p. 3, 21 February 2009.
^Breashears, David; Salkeld, Audrey (2000), Mallorys Geheimnis. Was geschah am Mount Everest?, Munich: Steiger,
ISBN978-3-89652-220-7.
Hinks, Arthur R. (1898b), "A Diagram showing the Conditions under which Observations for the Determination of Stellar Parallax are to be made", Monthly Notices of the Royal Astronomical Society, 58 (8): 440–43,
Bibcode:
1898MNRAS..58..440H,
doi:10.1093/mnras/58.8.440.
Hinks, Arthur R. (1901b), "Experimental Reduction of some Photographs of Eros made at the Cambridge Observatory for the Determination of the Solar Parallax", Monthly Notices of the Royal Astronomical Society, 62: 22–41,
Bibcode:
1901MNRAS..62...22H,
doi:10.1093/mnras/62.1.22.
Hinks, Arthur R. (1902b), "Experimental Reduction of Photographs of Eros for the Determination of the Solar Parallax. Second Paper: Combination of results from Mount Hamilton, Minneapolis, and Cambridge", Monthly Notices of the Royal Astronomical Society, 62 (8): 545–61,
Bibcode:
1902MNRAS..62..551F,
doi:10.1093/mnras/62.8.551.
Hinks, Arthur R. (1903a), "A Graphical Method of Applying to Photographic Measures the Terms of the Second Order in the Differential Refraction", Monthly Notices of the Royal Astronomical Society, 63 (3): 138–47,
Bibcode:
1903MNRAS..63..138H,
doi:10.1093/mnras/63.3.138.
Hinks, Arthur R. (1904c), "Reduction of 295 Photographs of Eros made at Nine Observatories during the period 1900 November 7–15, with a determination of the Solar Parallax", Monthly Notices of the Royal Astronomical Society, 64 (8): 701–27,
Bibcode:
1904MNRAS..64..701H,
doi:10.1093/mnras/64.8.701.
Hinks, Arthur R. (1906b), "Solar Parallax Papers, No. 5. Examination of the Photographic Places of Stars published in the Paris Eros Circulars", Monthly Notices of the Royal Astronomical Society, 67: 70–119,
Bibcode:
1906MNRAS..67...70H,
doi:10.1093/mnras/67.1.70.
Hinks, Arthur R. (1909a), "Solar parallax papers, No. 7. The General Solution from the Photographic Right Ascensions of Eros, at the Opposition of 1900", Monthly Notices of the Royal Astronomical Society, 69 (7): 544–67,
Bibcode:
1909MNRAS..69..544H,
doi:10.1093/mnras/69.7.544.
Hinks, Arthur R. (1910b), "Solar parallax papers, No. 9. The General Solution from the Micrometric Right Ascensions of Eros, at the opposition of 1900", Monthly Notices of the Royal Astronomical Society, 70 (8): 588–603,
Bibcode:
1910MNRAS..70..588H,
doi:10.1093/mnras/70.8.588.
Hinks, Arthur R. (1915b), "Some questions relating to the Shape of the Earth, suggested by Mr. Harold Jeffreys' paper "Certain hypotheses as to the structure of the Earth and the Moon"", Monthly Notices of the Royal Astronomical Society, 76: 8–13,
Bibcode:
1915MNRAS..76....8H,
doi:10.1093/mnras/76.1.8.
Hinks, Arthur R. (1927), New geodetic tables for Clarke's figure of 1880, with transformation to Madrid 1924, London: Royal Geographical Society,
Bibcode:
1927ngtc.book.....H.
Hinks, Arthur Robert, ed. (1938), Hints to travellers. volume 2: Organization and Equipment; Scientific Observation; Health, Sickness and Injury, London: Royal Geographical Society.
Further reading
"Obituary", Geographical Journal, 105: 146–51, 1945, includes wholeplate b/w photograph.