The following first hand account of Bacon was written by Francis Osborne, and was published in Part II p67 of his Advice to a Son (1658). The book is likely to have been composed some time before the date of its publication. Osborne was born in 1593, and died in 1659.
" 21. It is recorded of Solomon, that God had given him a large heart, through which he became universally knowing from the most despicable herb, to the highest cedar, and deepest secret in nature (then) under knowledge. Which may serve to answer their curiousity, who think they have done something towards the confutation of this assertion of his wisdom, when they find his sayings paralleled in other authors: since it is a sufficient manifestation of God's extraordinary grace upon him, that we are assured from his own writings, no less than from the testimony of the Sacred Scriptures, that part of the whole mass of human learning lay included in his person; and so, if equalled in one endowment, he was not exceeded by any single individual in the general knowledge of all. And as this appears by the Donor, to be none of the smallest gifts, no less than in the estimation of Solomon that did ask it, so may we strongly presume that an universal inspection is the most becoming quality a gentleman (unfixed in a settled calling) can bestow his endeavors upon. And my memory neither doth nor (I believe possible ever can) direct me towards an example more splendid in this kind, than the Lord Bacon, Earl of St Albans, who in all companies did appear a proficient, if not a master in those arts entertained for the subject of every one's discourse. So as I dare maintain, without the least affectation of flattery or hyperbole, that his most casual talk deserved to be written. As I have been told, his first our foulest copies required no great labour to render them compentent for the nicest judgements. A high perfection, attainable only by use, and treating with every man in his respective profession, and what he was most versed in. So as I have heard him entertain a Country Lord in the proper terms relating to Hawks and Dogs, and at another time out-cant a London Chirurgeon. Thus he did not only learn himself, but gratify such as taught him, who looked upon their callings as honored through his notice. Nor did any easy falling into arguments (but unjustly taken for a blemish in the most) appear less than an ornament to him: the ears of the hearer receiving omre gratification, than trouble: and (so) no less sorry when he came to conclude, than displeased with any did interrupt him. Now this general knowledge that he had in all things, husbanded by his wit, and diginifed by so majestical a carriage he was known to own, strook such an awful reverence in those h e questioned, that they durst not conceal the most intrinsic part of their Mysteries from him, for fear of appearing ignorant, or saucy.