The October 2020 provenance mystery features Thomas Hood’s The making and use of the geometricall instrument, called a sector, printed in London by John Windet in 1598.
This Thomas Hood (active 1582-1598) is not to be confused with the poet of the same name (1799-1845). According to Erwin Tomash and Michael R. Williams, the sector was a calculating instrument in use from the 16th to the 21st century and is also known as a proportional compass. While Galileo Galilei is often cited as the first inventor of the sector, Hood’s invention is contemporary to Galileo’s and Hood was the first to publish a book about his invention; Galileo was notoriously secretive about his knowledge and instruments. The sector could be purchased in London from Charles Whitwell (active 1594-1606) and Robert Becket. Whitwell lived ‘without Temple Barre against St. Clement’s Church’ in 1598. Whitwell’s sector can be viewed at the Science Museum. Edmund Gunter (1581-1626), in 1624, proposed a design of the sector which now tends to be the most well-known version.
Thomas Hood was a lecturer in mathematics for the City of London. In his inaugural address of 1558 he declared: ‘the Lawyer thinketh him selfe cunning enough to handle his case, and therefore would laugh, if he should heere, that he standeth in need of our profession [i.e. mathematicians], yet have I knowne his sentence re-claimed by one of my coate’.
The mystery surrounding this book concerns the extensive contemporary manuscript notes found at the end of it. There are four pages of notes written and signed by a ‘D.G.’. The notes are headed: ‘In all eight lined tryangles the proportion of one syde to an other is such as the sine of of the angle, representing the one syde, hath to the sine of the angle each pertinge the other syde’. The notes then go on to discuss this theorem. But who was ‘D.G.’ (or D.C. or in a pinch b.C.)? They have gone to the trouble of writing out very comprehensive notes on this theorem, including illustrating the notes with quite beautiful diagrams. Was it a fellow mathematician? A contemporary of Hood? An instrument maker? Unfortunately there is simply not enough information in the book to give us any further clues.
As ever, if you have any comments on this provenance mystery, contact the library at: firstname.lastname@example.org.