I pray also at your leasure answere the other pointes of my last letter concerning Vieta, Kepler and your selfe.  I have nothinge to presence you in counter, but gratitude with a will in act to be vsefull vnto you and a power in proxima potentia ; wch I will not leaue also till I haue broughte ad actum.  If you in the meane time can further it, tell wher in I may doe you seruice, and see how wholie you shall dispose of me.

Your most assured and louing friend
Tra’uenti the longest day of, 1610.  Willm Lower.
~ Addressed: To his espesial good frind
Mr. Thomas Hariot

Seal of Arms, (B.  M. Add. 6789.) at Sion neere London.

[Tra’venti or Trafenty, near Lower Court, is eight or nine miles south-west of Caermarthen, near the confluence of the rivers Taf and Cywyn.]

The writer is fortunately able to throw some light upon these letters of Lower to Hariot.  In the Monatlicbe Correspondenz Vol. 8, 1803, published by F. X. von Zach at Gotha, pages 47-56, is a most interesting fragment of an original letter inEnglish toHariot.  Dr Zach says that he found this letter at Petworth in 1784, and it being without date or signature he confidently assigned its authorship to the Earl of Northumberland, and guessed the date to have been prior to 1619.  In his many notes he is in raptures over his discovery, and deplores the misfortune of its breaking off in the most interesting place just as the Earl was about to announce the discovery of the elliptical orbit of the comet of 1607, as reasoned out of Hariot’s observations and the writings of Kepler.  This famous letter has been used or copied in many places, particularly in Ersch and Gru-ber’s Algemeine Encyklopadie under Hariot.

The mystery is now solved by giving here the letter in full.  It is even more important than Dr Zach with all his enthusiasm supposed.  It is not, however, from the pen of Northumberland, though none the less interesting on that account.  The letter is in the well-known handwriting of Lower, of Tra’venti, on Mount Martin, near Llanfihangel, in South Wales, to his dearly loved friend and master Hariot at Sion, and is dated the 6th of February, 1610.  The letter fills two sheets of foolscap paper.  The first sheet of four pages Dr Zach found at Petworth, and it is to be hoped that it still exists there.  The other sheet of four pages is preserved in the British Museum (Add. 6789).  How long these two sheets have been separated it is difficult to tell, but probably from Hariot’s day, that is, for more than two centuries and a half.  The two fragments are now brought together and printed for the first time complete, the first half from Dr Zach’s text, and the latter half copied verbatim direct from the original autograph manuscript, Brit.  Mus.  Add. 6789.

LETTER FROM SIR WILLIAM LOWER MATHEMATICIAN

AND ASTRONOMER TO THOMAS HARIOT AT SION