This _Sagredus_ (Iohannes Franciscus), or Sagredo (Giovanni Francisco), besides being “a great magneticall man,” was a noble Venetian, even a doge, and had represented his country as ambassador at several courts. We read in Mr. Conrad W. Cooke’s very able article on William Gilbert of Colchester, originally printed in London “Engineering,” that this same _Sagredus_ was the intimate friend of Galileo, and that, together with the powerful Sarpi, he used the whole might of his name and influence to protect the great philosopher and mathematician from the attacks of the clerical party. Pietro Sarpi, otherwise known as Father Paul, was, as already shown, a most illustrious Venetian scholar, who attained great proficiency in the medical and physiological sciences as well as in mathematics and in natural philosophy. _Sagredus_ made several meritorious researches in magnetism, and, while on a voyage to Aleppo, ascertained the declination of the magnetic needle at that place. As a tribute to the scientific attainments of _Sagredus_, Galileo gave his name to one of the characters in his “Systema Cosmicum,” and many references to the work by William Gilbert are put into the mouth of _Sagredus_. In further illustration of Galileo’s appreciation of Gilbert, the following is quoted from the great astronomer’s own writing: “I extremely admire and envy the author of ‘De Magnete.’ I think him worthy of the greatest praise for the many new and true observations which he has made, to the disgrace of so many vain and fabling authors, who write not from their own knowledge only, but repeat everything they hear from the foolish and vulgar, without attempting to satisfy themselves of the same by experience; perhaps that they may not diminish the size of their books” (Drinkwater’s “Life of Galileo”). Galileo had also published, in 1630, the first edition of his “I discorsi e demonstrazioni ...” which Lagrange considers to be Galileo’s most substantial title to scientific glory.