What Signor Porta extensively presents in his

Preface.

Namely, that he wrote this book in the fifteenth year of his age, and that the same so pleased everyone immediately that it was straightway translated into the Italian, French, Spanish, and Arabic languages and brought to press; but that afterwards, in the fiftieth year of his age, he had the same printed again in an improved form: Furthermore, that for its composition he not only most diligently read through the ancient writings and placed the best from them herein, but also on his travels through Italy, France, and Spain, diligently visited the most principal libraries and the most learned people, learned many things from all manner of artisans, and exchanged many letters with those with whom he was not personally

acquainted; he also applied all possible skill and diligence to learn of all manner of new inventions and arts through entreaties, gifts, and exchanges: Also, that he afterwards put the matters and pieces themselves to the test and examined them, expending great pains by day and night and much expense, and also received noble assistance therein from other personages of rank, and employed many clever and practiced people for the manual labor: No less that he, on this account, though innocently, was even decried as a sorcerer, and in what manner he refutes the same: all this we have, for the sake of beloved brevity, diligently omitted here, and thus proceed to the work itself, the