Dokumente zur Revalidierung von Thomas Harriot als Algebraiker

Summary

The mathematician Thomas Harriot has hitherto been evaluated almost exclusively from his Artis analyticœ praxis, which in 1631 was published posthumously from an imperfect manuscript. In this praxis algebraic equations and their solutions are discussed, but negative and complex roots are almost entirely neglected. However, Harriot's manuscripts (Add 6782–9 Br. Mus. and H.M.C. 240 and 241, Petworth House) reveal that Harriot in his own working papers listed negative roots and in many cases also complex roots. Also in other respects Harriot had a better understanding of algebraic equations than appears from the praxis. According to its title page, this work was composed as a textbook for the instruction of the Earl of Northumberland. Harriot may not have thought it advisable to introduce in such a book numbers which were more difficult to visualize than natural numbers, fractions, and positive roots.

The author has discovered manuscript passages (in papers of Torporley, Cavendish, Pell etc.) which indicate that transcripts from Harriot's unpublished works circulated among several mathematicians and amateurs in the seventeenth century.

It is curious that John Wallis, commenting on Harriot's algebraical innovations, gives a description which conforms much better with Harriot's algebraical manuscripts (notably Ms. Add 6783) than with the printed praxis. Since Wallis mostly denied all knowledge of Harriot's manuscripts, documents reflecting on the moral character and trustworthiness of Wallis have been added to the other documentary evidence of this article.