Editing Henry John Stephen Smith

{{Short description|British mathematician (1826–1883)}}
{{Use dmy dates|date=October 2019}}
{{Infobox scientist
| name              = Henry John Stephen Smith
| honorific_suffix  = {{post-nominals|country=GBR|FRS|FRSE|FRAS|size=100%}}
| image             = HenryJohnStephenSmith2.jpg
| image_size        = 
| caption           = 
| birth_date        = {{Birth date|1826|11|02|df=y}}
| birth_place       = [[Dublin]], [[Ireland]]
| death_date        = {{Death date and age|1883|02|09|1826|11|02|df=y}}
| death_place       = [[Oxford]], [[Oxfordshire]], [[England]]<ref>GRO Register of Deaths: MAR 1883 3a 511 OXFORD – Henry John S. SMITH, aged 56</ref>
| resting_place     = [[St Sepulchre's Cemetery]], [[Oxford]]
| residence         = 
| citizenship       = 
| nationality       = 
| ethnicity         = 
| field             = [[Mathematics]]
| work_institutions = [[University of Oxford]]
| alma_mater        = [[Balliol College, Oxford]]
| doctoral_advisor  = 
| doctoral_students = 
| known_for         = [[Smith–Minkowski–Siegel mass formula]]<br />[[Smith normal form]]<br />[[Smith–Volterra–Cantor set]]
| author_abbrev_bot = 
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| influences        = 
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| religion          = 
| footnotes         = 
| signature         = 
}}

'''Henry John Stephen Smith''' (2 November 1826 – 9 February 1883) was an Irish [[mathematician]] and amateur astronomer remembered for his work in [[elementary divisors]], [[quadratic form]]s, and [[Smith–Minkowski–Siegel mass formula]] in [[number theory]]. In [[Matrix (mathematics)|matrix theory]] he is visible today in having his name on the [[Smith normal form]] of a [[Matrix (mathematics)|matrix]].  Smith was also first to discover the [[Cantor set]].<ref>{{cite journal | first=Henry J.S. | last=Smith | date=1874 | title=On the integration of discontinuous functions | journal=Proceedings of the London Mathematical Society | series=First series | volume=6 | pages=140–153| url=https://zenodo.org/record/1932560 }}</ref><ref>{{Cite journal|url=https://doi.org/10.1080/0025570X.1994.11996201|title=A Note on the History of the Cantor Set and Cantor Function|first=Julian F.|last=Fleron|date=1 April 1994|journal=Mathematics Magazine|volume=67|issue=2|pages=136–140|via=Taylor and Francis+NEJM|doi=10.1080/0025570X.1994.11996201|url-access=subscription}}</ref><ref>[https://www.maa.org/press/periodicals/convergence/the-cantor-set-before-cantor-a-mini-primary-source-project-for-analysis-and-topology-students The Cantor Set Before Cantor] Mathematical Association of America</ref>

==Life==

Smith was born in [[Dublin]], [[Ireland]], the fourth child of John Smith (1792–1828), a [[barrister]], who died when Henry was two. His mother, Mary Murphy (d.1857) from [[Bantry Bay]],<ref name="auto">{{Cite web | url=http://www-history.mcs.st-and.ac.uk/Biographies/Smith.html |title = Henry Smith (1826-1883)}}</ref> very soon afterwards moved the family to England. He had thirteen siblings, including [[Eleanor Smith (activist)|Eleanor Smith]], who became a prominent educational activist.  He lived in several places in England as a boy. His mother did not send him to school but educated him herself until age 11, at which point she hired private tutors. At age 15 Smith was admitted in 1841 to [[Rugby School]] in [[Warwickshire]], where [[Thomas Arnold]] was the school's [[headmaster]]. This came about because his tutor [[Henry Highton]] took up a [[housemaster]] position there.<ref>{{ODNBweb|id=13250|title=Highton, Henry|first=Peter|last=Osborne}}</ref><ref>{{cite web| url=https://archive.org/stream/collectedmathema01smituoft#page/n21/mode/2up | title=Biographical sketch | work=The Collected Mathematical Works of Henry John Stephen Smith | editor-first=J. W. L. | editor-last=Glaisher | year=1894 | access-date=27 November 2012 | publisher=Oxford Clarendon Press }}</ref>

At 19 he won an entrance scholarship to [[Balliol College, Oxford]]. He graduated in 1849 with high honours in both mathematics and classics. Smith was fluent in French having spent holidays in [[France]], and he took classes in mathematics at the [[Collège de Sorbonne|Sorbonne]] in Paris during the 1846–7 academic year. He was unmarried and lived with his mother until her death in 1857. He then brought his sister, Eleanor Smith, to live with him as housekeeper at St Giles.<ref name="auto"/>

[[File:Henry John Stephen Smith.jpg|thumb|265px|Bust on display in the [[Oxford University Museum]].]]
Smith remained at Balliol College as a mathematics tutor following his graduation in 1849 and was soon promoted to [[Fellow (college)|Fellow]] status.

In 1861, he was promoted to the [[Savilian Chair of Geometry]] at [[University of Oxford|Oxford]]. In 1873, he was made the beneficiary of a fellowship at [[Corpus Christi College, Oxford]], and gave up teaching at Balliol.

In 1874 he became Keeper of the University Museum and moved (with his sister) to the Keeper's House on South Parks Road in Oxford.<ref name="auto"/>

On account of his ability as a man of affairs, Smith was in demand for academic administrative and committee work: he was [[Keeper (museum)|Keeper]] of the [[Oxford University Museum]]; a Mathematical Examiner for the [[University of London]]; a member of a Royal Commission to review scientific education practice; a member of the commission to reform [[University of Oxford]] governance; chairman of the committee of scientists overseeing the [[Meteorological Office]]; twice president of the [[London Mathematical Society]]; etc.

He died in Oxford on 9 February 1883. He is buried in [[St Sepulchre's Cemetery]] in Oxford.

==Work==

===Researches in number theory===
''An overview of Smith's mathematics contained in a lengthy obituary published in a professional journal in 1884 is reproduced at NumberTheory.Org.<ref>{{cite journal| url=http://www.numbertheory.org/obituaries/OTHERS/smith/page4.html | journal=[[Monthly Notices of the Royal Astronomical Society]] | date=February 1884 | title=Sixty-fourth Annual General Meeting | volume=XLIV | pages=138–149 | doi = 10.1093/mnras/44.4.138| doi-access=free }}</ref> The following is an extract from it.''

Smith's two earliest mathematical papers were on geometrical subjects, but the third concerned the theory of numbers. Following the example of Gauss, he wrote his first paper on the theory of numbers in Latin: "De compositione numerorum primorum formæ <math>4n+1</math> ex duobus quadratis." In it he proves in an original manner the theorem of Fermat---"That every prime number of the form <math>4n+1</math> (<math>n</math> being an integer) is the sum of two square numbers." In his second paper he gives an introduction to the theory of numbers.

In 1858, Smith was selected by the [[British Association]] to prepare a report upon the Theory of Numbers. It was prepared in five parts, extending over the years 1859–1865. It is neither a history nor a treatise, but something intermediate. The author analyzes with remarkable clearness and order the works of mathematicians for the preceding century upon the theory of congruences, and upon that of binary quadratic forms. He returns to the original sources, indicates the principle and sketches the course of the demonstrations, and states the result, often adding something of his own.

During the preparation of the Report, and as a logical consequence of the researches connected therewith, Smith published several original contributions to the higher arithmetic. Some were in complete form and appeared in the ''Philosophical Transactions'' of the Royal Society of London; others were incomplete, giving only the results without the extended demonstrations, and appeared in the Proceedings of that Society. One of the latter, entitled "On the orders and genera of quadratic forms containing more than three indeterminates," enunciates certain general principles by means of which he solves a problem proposed by [[Gotthold Eisenstein|Eisenstein]], namely, the decomposition of integer numbers into the sum of five squares; and further, the analogous problem for seven squares. It was also indicated that the four, six, and eight-square theorems of Jacobi, Eisenstein and Liouville were deducible from the principles set forth.

In 1868, Smith returned to the geometrical researches which had first occupied his attention. For a memoir on "Certain cubic and biquadratic problems" the Royal Academy of Sciences of Berlin awarded him the Steiner prize.

In February, 1882, Smith was surprised to see in the ''Comptes rendus'' that the subject proposed by the Paris Academy of Science
for the ''Grand prix des sciences mathématiques'' was the theory of the decomposition of integer numbers into a sum of five squares; and that the attention of competitors was directed to the results announced without demonstration by Eisenstein, whereas nothing was said about his papers dealing with the same subject in the Proceedings of the Royal Society. He wrote to M. Hermite calling his attention to what he had published; in reply he was assured that the members of the commission did not know of the existence of his papers, and he was advised to complete his demonstrations and submit the memoir according to the rules of the competition. According to the rules each manuscript bears a motto, and the corresponding envelope containing the name of the successful author is opened. There were still three months before the closing of the ''concours'' (1 June 1882) and Smith set to work, prepared the memoir and despatched it in time.

Two months after Smith's death, the [[Paris Academy]] made their award. Two of the three memoirs sent in were judged worthy of the prize. When
the envelopes were opened, the authors were found to be Smith and [[Hermann Minkowski|Minkowski]], a young mathematician of [[Königsberg]], [[Prussia]]. No notice was taken of Smith's previous publication on the subject, and M. Hermite on being written to, said that he forgot to bring the matter to the notice of the commission.

===Work on the Riemann integral===
In 1875 Smith published the important paper {{harv|Smith|1875}} on the integrability of [[discontinuous function]]s in [[Riemann integral|Riemann's sense]].<ref>See {{harv|Letta|1994|p=154}}.</ref> In this work, while giving a rigorous definition of the Riemann integral as well as explicit rigorous proofs of many of the results published by Riemann,<ref>The Riemann integral was introduced in Bernhard Riemann's paper "Über die Darstellbarkeit einer Function durch eine trigonometrische Reihe" (On the representability of a function by a trigonometric series), submitted to the University of Göttingen in 1854 as Riemann's ''Habilitationsschrift'' (qualification to become an instructor). It was published in 1868 in ''Abhandlungen der Königlichen Gesellschaft der Wissenschaften zu Göttingen'' (Proceedings of the Royal Philosophical Society at Göttingen), vol. 13, pages 87–132 (freely available on-line from [[Google Books]] [https://books.google.com/books?id=PDVFAAAAcAAJ&pg=RA1-PA87  here]): Riemann's definition of the integral is given in section 4, "Über der Begriff eines bestimmten Integrals und den Umfang seiner Gültigkeit" (On the concept of a definite integral and the extent of its validity), pp. 101–103, and {{harvtxt|Smith|1875|p=140}} analyzes this paper.</ref> he also gave an example of a [[meagre set]] which is not [[negligible set|negligible]] in the sense of [[measure theory]], since its measure is not zero:<ref name="Letta156">See {{harv|Letta|1994|p=156}}.</ref> a function which is everywhere continuous except on this set is not Riemann integrable. Smith's example shows that the proof of sufficient condition for the Riemann integrability of a discontinuous function given earlier by [[Hermann Hankel]] was incorrect and the result does not hold:<ref name="Letta156" /> however, his result remained unnoticed until much later, having no influence on successive developments.<ref>See {{harv|Letta|1994|p=157}}.</ref> In an 1875 paper, he discussed a nowhere-dense set of positive measure on the real line, an early version of the Cantor set, now known as the [[Smith–Volterra–Cantor set]].

==Publications==

*{{cite journal|author=Smith, H. J. S.|title=Note on continued fractions|journal=The Messenger of Mathematics|year=1874|volume=6|pages=1–13|url=https://www.math.ubc.ca/~cass/smith/smith.html}}
*{{Citation
 | last = Smith
 | first = H. J. S.
 | title = On the integration of discontinuous functions
 | journal = [[Proceedings of the London Mathematical Society]]
 | volume = 6
 | pages = 140–153
 | year = 1875
 | url = https://babel.hathitrust.org/cgi/pt?id=ucm.5324906759;view=1up;seq=148
 | jfm = 07.0247.01}}.
*{{Citation | last1=Smith | first1=Henry John Stephen | editor1-last=Glaisher | editor1-first=J. W. L. | title=The Collected Mathematical Papers of Henry John Stephen Smith | orig-year=1894 | url=https://www.ams.org/bookstore-getitem/item=CHEL-187 | publisher=AMS Chelsea Publishing | location=New York | isbn=978-0-8284-0187-6 | id=[https://archive.org/details/collectedmathema01smituoft volume 1][https://archive.org/details/collectedmathema02smituoft volume 2] | year=1965 | volume=I, II}}

== See also ==
*[[Smith–Volterra–Cantor set]]

==Notes==
{{Reflist|29em}}

==References==
*J.T.Fleron, "A Note on the History of the Cantor Set and Cantor Function", ''Math Magazine'', Vol 67, No. 2, April 1994, 136–140. 
*H.J.S. Smith: "On the Integration of Discontinuous Functions", ''Proceedings London Mathematical Society'', (1875) 140–153.
*K. Hannabuss, "Forgotten fractals", ''The Mathematical Intelligencer'', 18 (3) (1996), 28–31.
*{{Citation
 |last        = Letta
 |first       = Giorgio
 |author-link = Giorgio Letta
 |title       = Le condizioni di Riemann per l'integrabilità e il loro influsso sulla nascita del concetto di misura
 |trans-title = Riemann's conditions for integrability and their influence on the birth of the concept of measure
 |journal     = [[Rendiconti della Accademia Nazionale delle Scienze Detta dei XL, Memorie di Matematica e Applicazioni]]
 |volume      = XVIII
 |issue       = 1
 |pages       = 143–169
 |orig-year    = 112°
 |year        = 1994
 |language    = it
 |url         = http://media.accademiaxl.it/memorie/Serie5_V18_P1.pdf
 |mr          = 1327463
 |zbl         = 0852.28001
 |url-status     = dead
 |archive-url  = https://web.archive.org/web/20140228144250/http://media.accademiaxl.it/memorie/Serie5_V18_P1.pdf
 |archive-date = 28 February 2014
 |df          = dmy-all
}}. An article on the history of measure theory, analyzing deeply and comprehensively every early contribution to the field, starting from Riemann's work and going to the works of [[Hermann Hankel]], [[Gaston Darboux]], [[Giulio Ascoli]], Henry John Stephen Smith, [[Ulisse Dini]], [[Vito Volterra]], [[Paul David Gustav du Bois-Reymond]] and [[Carl Gustav Axel Harnack]].

==Further reading==
*{{Citation | last1=Glaisher | first1=J. W. L. | title=Obituary of Henry John Stephen Smith | url=http://www.numbertheory.org/obituaries/OTHERS/smith/ | year=1884 | journal=[[Monthly Notices of the Royal Astronomical Society]] | volume= XLIV | pages=138–149 | doi=10.1093/mnras/44.4.138| doi-access=free }}
*{{Citation | last1=Macfarlane | first1=Alexander | title=Lectures on Ten British Mathematicians of the Nineteenth Century | orig-year=1916 | url=https://archive.org/details/lecturesontenbri00macf | publisher=Cornell University Library | series=Mathematical monographs | isbn=978-1-112-28306-2 | year=2009 | volume=17}} ([http://webarchive.nationalarchives.gov.uk/20140204210129/http://library.beau.org/gutenberg/etext06/tbmms10p.pdf complete text] at [[Project Gutenberg]])
* {{MacTutor Biography|id=Smith}}

==External links==
{{wikiquote}}
{{EB1911 poster|Smith, Henry John Stephen}}
* [http://www.stsepulchres.org.uk/burials/smith_henry_john.html The grave of Henry John Stephen Smith and his sister Eleanor in St Sepulchre's Cemetery, Oxford, with biography]
* [[q:Henry John Stephen Smith|Henry John Stephen Smith]] at [[Wikiquote]]

{{Savilian Professors of Geometry}}

{{Authority control}}

{{DEFAULTSORT:Smith, Henry John Stephen}}
[[Category:1826 births]]
[[Category:1883 deaths]]
[[Category:Scientists from County Dublin]]
[[Category:People educated at Rugby School]]
[[Category:Alumni of Balliol College, Oxford]]
[[Category:19th-century British mathematicians]]
[[Category:British number theorists]]
[[Category:Presidents of the Oxford Union]]
[[Category:Savilian Professors of Geometry]]
[[Category:Fellows of Balliol College, Oxford]]
[[Category:Fellows of Corpus Christi College, Oxford]]
[[Category:Directors of museums in the United Kingdom]]
[[Category:Fellows of the Royal Society]]
[[Category:Presidents of the London Mathematical Society]]
[[Category:19th-century British businesspeople]]
[[Category:Burials at St Sepulchre's Cemetery]]