Editing Parallel (geometry) (section)

==Notes==
{{Reflist|refs=
<ref name="Kersey_1673">{{cite book |author-first=John |author-last=Kersey (the elder) |author-link=John Kersey the elder |title=Algebra |location=London |date=1673 |volume=Book IV |page=177}}</ref>
<ref name="Cajori_1928">{{cite book |author-first=Florian |author-last=Cajori |author-link=Florian Cajori |title=A History of Mathematical Notations - Notations in Elementary Mathematics |chapter=§ 184, § 359, § 368 |volume=1 |orig-year=September 1928 |publisher=[[Open court publishing company]] |location=Chicago, US |date=1993 |edition=two volumes in one unaltered reprint |pages=[https://archive.org/details/historyofmathema00cajo_0/page/193 193, 402–403, 411–412] |isbn=0-486-67766-4 |lccn=93-29211 |chapter-url=https://archive.org/details/historyofmathema00cajo_0/page/193 |access-date=2019-07-22 |quote=§359. […] ∥ for parallel occurs in [[William Oughtred|Oughtred]]'s ''Opuscula mathematica hactenus inedita'' (1677) [p. 197], a posthumous work (§ 184) […] §368. Signs for parallel lines. […] when [[Robert Recorde|Recorde]]'s sign of equality won its way upon the Continent, vertical lines came to be used for parallelism. We find ∥ for "parallel" in [[John Kersey the elder|Kersey]],[14] [[John Caswell|Caswell]], [[William Jones (mathematician)|Jones]],[15] Wilson,[16] [[William Emerson (mathematician)|Emerson]],[17] Kambly,[18] and the writers of the last fifty years who have been already quoted in connection with other pictographs. Before about 1875 it does not occur as often […] Hall and Stevens[1] use "par[1] or ∥" for parallel […] [14] [[John Kersey the elder|John Kersey]], ''Algebra'' (London, 1673), Book IV, p. 177. [15] [[William Jones (mathematician)|W. Jones]], ''Synopsis palmarioum matheseos'' (London, 1706). [16] John Wilson, ''Trigonometry'' (Edinburgh, 1714), characters explained. [17] [[William Emerson (mathematician)|W. Emerson]], ''Elements of Geometry'' (London, 1763), p. 4. [18] {{ill|Ludwig Kambly{{!}}L.<!-- Ludwig --> Kambly|de|Ludwig Kambly}}, ''Die Elementar-Mathematik'', Part 2: ''Planimetrie'', 43. edition (Breslau, 1876), p. 8. […] [1] H. S.<!-- Henry Sinclair --> Hall and F. H.<!-- Frederick Haller --> Stevens, ''Euclid's Elements'', Parts I and II (London, 1889), p. 10. […] }} [https://monoskop.org/images/2/21/Cajori_Florian_A_History_of_Mathematical_Notations_2_Vols.pdf]</ref>
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