Certa Mensura Cartuariensis

A 14ᵗʰ century manuscript from the monastery at Canterbury.

Certa mensura pollicis, palme, pedis, passus et aliorum

Mensura unius pollicis incipit ex transverso radicum unguium pollicis. Quator pollices unam palmam faciunt; quator palme unum pedem; pes et dimidius cubitum parvum faciunt; sex parvi cubiti cubitum magnum faciunt ; quinque pedes passum faciunt; centum viginti quique passus stadium unum; octo stadia unum miliare faciunt; duo miliare unam leucam complent. Et sic fuit Archa Noe de DXL. passibus, qui continent quator stadia et quadraginta passus secundum Hugonew de Sco. Victore.....

Memorandum quod ulna communis regni Anglie continenet tres pedes; et regia virga communis continent sexdecim pedes et dimidium. Item xl. virgate continenet unam quarentenam. Item septem quarentene et dimidia tres virgate dimidia pes continent unum miliare. Item duo miliaria continent unam leucam secundum geometriam.

The measure of one thumb-width originates as the width measured at the base of the nail. Four thumb’s-widths make 1 palm; four palms 1 foot; 1½ feet make a short cubit; 6 short cubits make a large cubit; 5 feet make a pace; 125 paces make a stade; 8 stades make 1 mile; 2 miles comprise a leuca. And thus the ark of Noah of 540 paces, which contains 4 stadia and 40 paces following Hugonew of…

It is to be recorded that the common yard of the English kingdom contains 3 feet, and the royal common perch contains 16½ feet. Item, 40 perch make 1 furlong. Moreover, 7½ furlongs, 3 perch and ½ feet make 1 mile. Moreover, 2 miles make 1 leuca following geometry.

Joseph Brigstocke Sheppard, ed.
Certa Mensura Cartuariensis.
Second Report on Historical Manuscripts belonging to the Dean and Chapter of Canterbury.
Appendix Pt. 1, page 325 of
Great Britain. Royal Commission on Historical Manuscripts.
Eighth Report of the Royal Commission on Historical Manuscripts. Report and Appendix.—(Part I.)
London: H.M.S.O., 1881.

A. De Morgan called attention to this source in 1839 in his article “League” in the Penny Cyclopaedia, vol. 13, page 376. However, the transcription in De Morgan's article differs considerably from that in the Eighth Report.

Notice that 7½ furlongs, 3 perch and ½ foot add up to a 5000-foot mile, following the Roman example (1000 paces).