This is an extract from a letter dated 28th January, 1837, from Panizzi to his Royal Highness the Duke of Sussex (then President of the Royal Society), a letter wherein is fully set forth his whole conduct in the case, and which, besides revealing the puerile and almost unpardonable errors he detected in the titles brought under his notice, is a wonderful certificate to the patience, endurance, and acuteness of a gentleman who was called upon to contend, single-handed, with a corporate body, supported by a clique necessarily jealous of its own distinction. We shall now explain as clearly as possible the course pursued by the Society, and the pains-taking, much enduring way in which Panizzi met his opponents. Let us, therefore, continue to extract from the memorable letter to H.R.H. the Duke of Sussex, those passages wherein are particularized the egregious blunders of Panizzi’s predecessor in the work:— “Authors’ names were not better treated than the subjects. Bonaventura, the Christian name of Cavalieri, was taken for a family name, and a cross reference put from it to Cavalieri; of the three mathematical _decades_ of Giovan Camillo Gloriosi, one was put under Camillo, his second Christian name, and the remainder under his family name Gloriosi. On entering a collection, the word Collezione was taken for a surname, and Nuova for a _christian_ name, and thus the entry is to be found “Collezione (N.)” I will not notice mere errors of the press, of which the number is prodigious; but there are entries which prove abundantly that the printer was not to be accused of them. Cossali’s History of Algebra in Italy was printed _Nella Real Tipografia Parmense_, and _Parmense_ was gravely inserted as the name of the place where the book was printed. Da Cunha’s mathematical principles were translated into French by D’Abreu after the author’s death, and have this title: “Principes Mathématiques de feu J. A. Da Cunha.” Anyone who has even merely heard of the “_feu_ Lord Maire de Londres” may easily guess, without much knowledge of French, that _feu_ here means _late_, _i.e._, _deceased_. The compiler of this Catalogue, however, did not attach such a gloomy meaning to this word; but philosophically conceived it to signify _fire_, as is evident by his precaution in writing it with a capital F, _Feu_; and by substituting the word _Opuscules_ for the correct one, _Principes_, the following entry was made:— “Da Cunha (J. A.), Opuscules Mathématiques de Feu, traduits littéralement du Portugais, par J. M. D’ Abreu. 8vo _Bordeaux_, 1811.