20
LETTERS ON SCIENTIFIC SUBJECTS.
DR. JOHN DEE TO CHARLES JACKMAN AND ARTHUR PETT.
[MS. Lansd. No. 122, Art. 5. Orig.]
Instructions for the two masters, Charles Jackman and Arthur Pett, geven and delyvered to them, at the Court day holden at the Moschovy house, the 17th of May, anno 1580, with which instructions a new charte (made by hand) was geven allso to eche of the sayd two Masters, expressing their Cathay voyage more exactly than any other yet published.
In the name of Jesus!
Yf we recken from Wardhouse to Colgoyeve Iland 400 myles, for allmost 20 degrees difference, only of longitude, very nere east and west, and abowt the latitude of 70⅔.
And from Colgoyeve to Vaygatz 200 myles, for 10 degrees difference (only in longitude) at 70 degrees of latitude allso.
And from Vaygatz to the promontory Tabin, being 60 degrees different in longitude; (the whole course or shortest distance betwene which two is allso east and west, in the latitude likewise of 70) are 1200 myles. Then is summa totalis from Wardhouse to Tabin, 600 leages or 1800 myles English.
Therefore allowing in a discovery voyage, for one day with an other, but 50 myles English; yt is evident that from Wardhouse to Tabin, the course may be sayled easily in 36 dayes. But by God's help, it may be fynisshed in much shorter tyme: both by help of wynde prosperous, and lyght continuall for the tyme requisite thereto.
When you are past Tabin, or come to the longitude of 142 (as your charte sheweth) or 2, 3, 4, or 5 degrees farder easterly, it is probable that you shall fynde the lande on your right hand, running much sowtherly and eastward, in which course you are like either to fall into the mowth of the famous ryver Oechardes, or some other: which (yet) I conjecture, to pas by the renowned City of Cambalu: and that mouth to be in the latitude abowt 50 or 52 degrees, and within 300 or 400 myles of Cambalu, ytself being in latitude abowt 45 de- [1]
- ↑ Jewel in the British Museum, mentions "old Humphrie Cole" as a "mathematical mechanician"; and he applies the same term to him in his work entitled Pierces Supererogation, 4to. Lond. 1593, p. 190. William Bourne also, in his Inventions or Devises, Lond. 1578, p. 17, makes honourable mention of him as an inventor. A mathematical-instrument-maker of the same name, living "neere unto the North dore" of St. Paul's, is mentioned by Worsop in his work entitled Discoverie of sundrie errors and faults daily committed by Lande-meater, 4to, Lond. 1582; but I am uncertain whether this latter notice refers to the same person.