TRACT 19. TRIGONOMETRICAL TABLES, &C. 303

author has relinquished in the new edition of his history. Butit may be said, what reason have we to suppose that this wordis either a Latin word, or the abbreviation of any Latin wordswhatever ? and that it seems but proper to seek for the ety-mology of words in the language of the inventors of the things.For which reason it is, that we find the two other words,tangens and secans, are Latin, as they were invented and usedby authors who wrote in that language. But the sines areacknowledged to have been invented and introduced by theArabians, and thence by analogy it would seem probable thatthis is a word of their language, and from them adopted, to-gether with the use of it, by the Europeans. And indeedLansberg, in the second page of his trigonometry above-mentioned, expressly says, that it is Arabic : His words are,Vox sinus Arabica est, et proinde barbara; sed cum longo usuapprobata sit, et commodior non suppetat, nequaquam repudi-anda est: faciles enim in verbis nos esse oportet, cum de rebusconvenit. And Vieta says something to the same purport, inpage 9 of his “ Universalium Inspcctionum ad CanonemMathematicum Liber:” His words are, Breve sinus vocabulum,cum sit artis, Saracenis prasertim quam familiare, non est abartificibus explodendum, ad laterum semissium inscriptorumdenotationem, fife.

Guarinus also is of the same opinion: in his cc EuclidesAdauctus,” &c. tract xx. pa. 307, he says, Sinus vero estnomen Arabicum usurpatum in lianc significationcm a mathe-maticis; though he was aware that a Latin origin was as-cribed to it by Vitalis, for he immediately adds, Licet Vitalisin suo Lexico Mathematico ex eo velit sinum appellatum, quodclaudat curvitatem arcus.

Long before I either saw or heard of any conjecture, orobservation, concerning the etymology of the word sinus, Iremember that I imagined it to be taken from the same Latinword, signifying breast or bosom, and that our sine was socalled allegorically. I had observed, that several of the termsin trigonometry were derived from a bow to shoot with, andits appendages; as arcus the bow, chorda the string, and