Catalogue Entry: THEM00067

Proposals concerning calendar reform

Author: Isaac Newton

• Three drafts of 'Considerations about rectifying the Iulian Kalendar' and an unrelated alchemical recipe
  [Normalized Text] [Diplomatic Text]
• 'The use of the Kalendar for finding the Lords day & the Moveable Feasts'
  [Normalized Text] [Diplomatic Text]
• Draft proposals for rectifying the Julian calendar
  [Normalized Text] [Diplomatic Text]
• Draft proposals for calendar reform
  [Normalized Text] [Diplomatic Text]
• 'Regulæ pro determinatione Paschæ' (draft and fair copy)
  [Normalized Text] [Diplomatic Text]
• Two drafts of a letter on calendar reform, with extraneous material concerning chronology and the Temple of Zerubbabel
  [Normalized Text] [Diplomatic Text]
• Draft letter concerning ancient calendars, and notes on Jewish chronology
  [Normalized Text] [Diplomatic Text]

Metadata: 1699 and later, mainly in English with some Latin , c. 18,997 words, 30 ff. of which 4 blank.

Source: Yahuda Ms. 24, National Library of Israel, Jerusalem, Israel

Custodial History

Bought at the Sotheby sale by Gabriel Wells for £54. Keynes asked to see it on 3 August 1936 but early in September he was informed that it had already been sold. On 4 November 1936 he asked Yahuda whether he had the lot and a week later Yahuda confirmed that he had. On 1 December Yahuda told him that he was sending him, as part of their exchange negotiations, lots 50 (now Keynes Ms. 35), 72 (now Keynes Ms. 44), 87 (now in the Boston Medical Library) and 222 (this manuscript), though in the event it would seem Keynes only kept the first two. See Spargo, '1936 sale', 130-32, where this manuscript is mistakenly referred to as SL225.

Sotheby Lot

SL222

Contents

A) 'Considerations about rectifying the Iulian Kalendar'. Two drafts and a fair copy, 10 pp. on 6 ff.; ff. 2v-2r (in that order) include part of an unrelated chemical text in Latin. On the deficiencies of both the Julian and the Gregorian calendars, with a proposed alternative to both.

B) 'The use of y^e Kalendar for finding the Lords day and the moveable Feasts': draft table and method for determining these dates in the proposed new calendar, on the wrapper of a letter to Lord Chief Justice Greby, 1 f.

C) Variant set of proposals for rectifying the Julian calendar, with a table collating a year by the Julian calendar with Newton's proposed revision, and various calculations, 2 ff.

Calculations and rough drafts relating to the proposed revision, 1 f.

Notes about feast days in the early Church, 2 ff.; on the last page some statistics apparently relating to the French navy.

D) Various related calculations, a table entitled 'Observationes Hipparchi', and two drafts of a memorandum on the advantages of Newton's proposed calendar; 4 ff. of which 1 blank.

E) Draft and fair copy: 'Regulæ pro determinatione Paschæ [in the fair copy 'Paschatis']', 4 ff. The fair copy is in another hand.

F) Two variant drafts of a letter [apparently to the Bishop of Worcester] on calendar reform, in English, 4 ff. of which one blank. The text is interspersed with draft passages about Jewish chronology and Ezekiel's temple, and on f. 1v there is a note about Mint salaries and expenses.

G) Draft of a letter concerning 'the Paper, which his Lord^p the B^p of Worcester [Edward Stillingfleet] sent to D^r Prideaux' (about ancient calendars), and Latin and English notes on Jewish chronology and the Temple of Zerubbabel, appended to the beginning of a draft letter addressed 'Reverendissimo Viro D. P. Allix S.T.D.' (i.e. Pierre Allix, with whom Newton corresponded in 1713), 2 ff.

Two wrappers, one with the heading in Thomas Pellet's hand: 'N^o 3 Considerations about the Iulian Calendar'.

Related Material

See Brewster (1855), 2: 311-12 for discussion of the contents and dating of these documents