During the years that followed he continued to contribute to the leading reviews, writing in the Monthly Review the articles on Robertson's Parian Chronicle, Edwards's Plutarch, and R. Payne Knight's Essay an the Greek Alphabet. He gave assistance to William Beloe in one or two articles in the Britirh Critic/e, and probably wrote also in the Analytical Review and the Critical Review.
In 1792 his fellowship was no longer tenable by a layman; and, rather than undertake duties for which he felt himself unfit, and which involved subscription to the Articles (though he had no difficulty as to signing a statement as to his conformity with the liturgy of the Church of England when elected Greek professor), he determined not to take holy orders, which would have enabled him to remain a fellow, and thus deprived himself of his only means of subsistence. He might have been retained in the society by being appointed to a lay fellowship, one of the two permanent lay fellowships which the statutes then permitted falling vacant just in time. It is said that this had been promised him, and it was certainly the custom in the college always to appoint the senior among the existing laymen, who otherwise would vacate his fellowship. But the master (Dr Postlethwaite), who had the nomination, used his privilege to nominate a younger man (John Heys), a nephew of his own, and thus Porson was turned adrift without any means of support. A subscription was, however, got up among his friends to provide an annuity to keep him from actual want; Cracherode, Cleaver Banks, Burney and Parr took the lead, and enough was collected to produce about £100 a year. He accepted it only on the condition that he should receive the interest during his lifetime, and that the principal, placed in the hands of trustees, should be returned to the donors at his death. When this occurred they or their survivors refused to receive the money, and it was with part of this sum that, in 1816, the Porson prize was founded to perpetuate his name at Cambridge. The remainder was devoted to the foundation of the Porson scholarship in the same university. This scholarship was first awarded in 1855.
After the loss of his fellowship he continued chiefly to reside in London, having chambers in Essex Court, Temple-occasionally visiting his friends, such as Dr Goodall at Eton and Dr Samuel Parr at Hatton. It was at Dr Goodall's house that the Letters to Travis were written, and at one period of his life he spent a great deal of time at Hatton. While there he would generally spend his mornings in the library, and for the most part in silence; but in the evenings, especially if Parr were away, he would collect the young men of the house about him, and pour forth from memory torrents of every kind of literature. The charms of his society are described as being then irresistible. In 1792 the Greek professorship at Cambridge became vacant by the resignation of Mr Cooke. To this Porson was elected without opposition, and he continued to hold it till his death. The duties then consisted in taking.a part in the examinations for the university scholarships and classical medals. It was said he wished to give lectures; but lecturing was not in fashion in those days, and he did far more to advance the knowledge and study of the Greek language by his publications than he could have done by any amount of lecturing. It must be remembered that the emoluments of the professorship were only £40 a year. The authors on which his time was chiefly spent were the tragedians, Aristophanes, Athenaeus, and the lexicons of Suidas, Hesychius and Photius. This last he twice transcribed (the first transcript having been destroyed by a fire at Perry's house, which deprived the world of much valuable matter that he had written on the margins of his books) from the original among the Gale MSS. in the library of Trinity College. Of the brilliancy and accuracy of his emendations on Aristophanes, the fragments of the other comic poets, and the lexicographers he had a pleasing proof on one occasion when he found how often in Aristophanes he had been anticipated by Bentley, and on another when Schow's collation of the unique MS. of Hesychius appeared and proved him right in “ an incredible number ” of instances.
In 1795 there appeared from Foulis's press at Glasgow an edition of Aeschylus in folio, printed with the same types as the Glasgow H omer, without a word of preface or anything to give a clue to the editor. Many new readings were inserted in the text with an asterisk affixed, while an obelus was used to mark many others as corrupt. It was at once recognized as Pors0n's work; he had superintended the printing of a small edition in two vols. 8vo, but this was kept back by the printer and not issued till 1806, still without the editor's name. There are corrections of many more passages in this edition than in the folio; and, though the text cannot be considered as what would have gone forth if with his name and sanction, yet more is done for the text of Aeschylus than had been accomplished by any preceding editor. It has formed the substratum for all subsequent editions. It was printed from a copy of Pauw's edition corrected, which is preserved in the library of Trinity College. Soon after this, in 1797, appeared the first instalment of what was intended to be a complete edition of Euripides-an edition of the H ecuba.
In the preface he pointed out the correct method of writing several words previously incorrectly written, and gave some specimens of his powers on the subject of Greek metres. The notes are very short, almost entirely critical; but so great a range of learning, combined with such felicity of emendation whenever a corrupt passage was encountered, is displayed that there was never any doubt as to the quarter whence the new edition had proceeded. He avoided the office of interpreter in his notes, which may well be wondered at on recollecting how admirably he did translate when he condescended to that branch of an editor's duties.
His work, however, did not escape attack; Gilbert Wakefield had already published a T ragoediarum deleetus; and, conceiving himself to be slighted, as there was no mention of his labours in the new H ecuba, he wrote a “ diatribe extemporalis ” against it, a tract which for bad taste, bad Latin and bad criticism it would not be easy to match. Gottfried Hermann of Leipzig, then a very young man, who had also written a work on Greek metres, which Dr Elmsley has styled “ a book of which too much ill cannot easily be said, ” issued an edition of the H eeuba, in which Porson's theories were openly attacked. Porson at first took no notice of either, but went on quietly with his Euripides, publishing the Orestes in 1798, the Phoenissae in 1799 and the Medea in 1801, the last printed at the Cambridge press, and with the editor's name on the title-page. But there are many allusions to his antagonists in the notes on such points as the nnal v, the use of accents, &c.; and on V. 675 of the Medea he holds up Hermann by name to scorn in caustic and taunting language. And it is more than probable that to Hermann's attack We owe the most perfect of his works, the supplement to the preface to the Heeuba, prefixed to the second edition published at Cambridge in 1802. The metrical laws promulgated are laid down clearly, illustrated with an ample number of examples, and those that militate against them brought together and corrected, so that what had been beyond the reach of the ablest scholars of preceding times is made clear to the tyro. The laws of the iambic metre are fully explained, and the theory of the pause stated and proved, which had been only alluded to in the first edition. A third edition of the H eeuba appeared in 1808, and he left corrected copies of the other plays, of which new editions appeared soon after his death; but these four plays were all that was accomplished of the projected edition of the poet. Person lived six years after the second edition of the Hecuba was published, but his natural indolence and procrastination led him to put off the work. He found time, however, to execute his collation of the Harleian MS. of the Odyssey, published in the Grenville Homer in 1801, and to present to the Society of Antiquaries his wonderful conjectural restoration of the Rosetta stone.
In 1806, when the London Institution was founded (then in the Old Jewry, since removed to Finsbury Circus), he was appointed principal librarian with a salary of £200 a year and a suite of rooms; and thus his latter years were made easy as far as money was concerned.