In 1808 an elaborate treatise was printed at Naples, by Flaminius Venanson with the title, _De l'invention de la Boussole Nautique_. Venanson, who cites many authorities, endeavours to prove that if Gioia did not discover magnetic polarity he at least invented the compass, that is to say, he pivotted the magnetic needle and placed it in a box, with a card affixed above it divided into sixteen parts bearing the names of the sixteen principal winds. He alleges in proof that the compass-card is emblazoned in the armorial bearings of the city of Amalfi. This view was combatted in the famous letter of Klaproth to Humboldt publisht in Paris in 1834. He shows that the use of the magnetized needle was known in Europe toward the end of the twelfth century; that the Chinese knew of it and used it for finding the way on land still earlier; that there is no compass-card in the arms of the city of Amalfi; but he concedes that Gioia may have improved the compass in 1302 by adding the wind-rose card. The most recent contributions to the question are a pamphlet by Signorelli, _Sull' invenzione della Bussola nautica, ragionamento di Pietro Napoli Signorelli, segretario perpetuo della Società Pontaniana; letto nella seduta del 30 settembre 1860_; Matteo Camera's _Memorie Storico-diplomatiche dell' antica città e ducato di Amalfi_ (Salerno, 1876); and Admiral Luigi Fincati's work _Il Magnete, la Calamita, e la Bussola_ (Roma, 1878). An older mention of Gioia is to be found in Blundevile's _Exercises_ (3rd edition, 1606, pp. 257-258). See also Crescentio _della Nautica Mediterranea_, (Roma, 1607, p. 253), and Azuni, _Dissertazione sull' origine della bussola nautica_ (Venezia, 1797). {9} There appears to be a slip in Gilbert's reference to Andrea Doria, as he has confounded the town of Amalfi in Principato Citra with Melfi in Basilicata. One of the sources relied upon by historians for ascribing this origin of the compass is the _Compendia dell' Istoria del Regno di Napoli_, of Collenuccio (Venet., MDXCI.), p. 5. "Nè in questo tacerò Amalfi, picciola terra, & capo della costa di Picentia, alia quale tutti quelli, che'l mar caualcano, vfficiosamente eterno gratie debono referire, essendo prima in quella terra trovato l'vso, & l'artificio della calamita, & del bussolo, col quale i nauiganti, la stella Tramontana infallibilmente mirando, direzzano il lor corso, si come è publica fama, & gli Amalfitani si gloriano, nè senza ragione dalli piu si crede, essendo cosa certa, che gli antichi tale instromento non hebbero; nè essendo mai in tutto falso quello, che in molto tempo è da molti si diuolga." Another account is to be found in the _Historiarum sui temporis_, etc., of Paulus Jovius (Florent., 1552), tom. ii., cap. 25, p. 42.