Harley MS 80, ff 1r-57r, ff 54v-57r

Richard of Wallingford, Tractatus rectanguli. Prologue 'Rectangulum in remedium tediosi & difficilis operis', rubric 'Capitulum primum de arte componendi tibiam primam', incipit: 'Ad componendum igitur rectangulum, separemus laminam', explicit (f. 57r) 'ponimus istic finem', followed (f. 57r) by a canon to the table of versed chords added in the 15th century, incipit. 'Est quedammodo tabula pro rectangulo brevis et utilis', explicit: 'in tabula non oportet bis intrare. Quidam Goldstone'. Goldstone is possibly identifiable with Thomas Goldstone (d. 1517), for whom see R. Sharpe, A Handlist of the Latin Writers of Great Britain and Ireland before 1540, Publications of the Journal of Medieval Latin, 1 (Turnhout: Brepols, 1997), p. 658. The date 'Ao 1326' supplied in the upper margin of f. 54v by a later hand.

The work is divided into 2 parts, each beginning respectivelly on ff. 54v, 55v, and subdivided into chapters (capitula).

Decoration:

Chapter initials (3 lines) in blue, with pen-flourished decoration in red extending into the margin. Space left for diagrams (ff. 54v-55r). Headings in red.