Wilhelm Steinitz discussed Frederic Deacon in the September 1891 issue of his International Chess Magazine.
The first, and as far as I recollect the only version of the dispute about the Deacon - Morphy games I heard from Deacon himself, and it is in brief as follows. Deacon stated that he played two games with Morphy on even terms of which each won one, but when they were published Morphy declared that he had never played with Deacon, and if he had been asked to play he would have only consented on the terms that Deacon should receive the odds of Pawn and move. Some public controversy arose in consequence, which, however, was practically stopped at least in England by a letter of Colonel Deacon, a brother of Mr. Deacon, to the Illustrated London News, which stated that he had seen Morphy playing with his brother at the latter's own house (if I remember rightly). The two flatly contradictorv statements could not well be reconciled, and perhaps there may be some Englishmen to the present day who believe that Morphy was not up to the truth in the matter, but 1 believe I can throw some light on the subject that will clear the American master from all suspicion with out impugning Colonel Deacon's veracity, though 1 must somewhat doubt his Chess understanding.
For I judge that Deacon played on Morphy a trick similar to the one which he practised upon myself in the following manner. Shortly after I had played my match with him in 1863 he invited my attention on one occasion when we were both alone in the rooms of the London Chess Club to a new move which he said he had invented in one of the openings. At that time a novelty in the openings was considered quite a revelation, and as I knew little of the books I got interested and consented at his request to examine the variation with him. It was a line of play in the King Knight opening for the defence, [ believe, which 1 have never adopted before or since in actual practice. Writing from recollection I think he assigned to me the defence after 1 P—K4, 1 P—K4: 2 K Kt— B3, 2 P—Q4, [1.e4 e5 2.Nc3 d5] and he claimed that he could improve on the book attack which he showed me first. In the skittle analysis which followed I demolished his suggested novelty in several main lines of play as well as in subvariations which he tried after taking moves back. But at last, probably owing to some thoughtless move which I had adopted in the investigation, he got hold of a better position and then he began to move slowly. But when I wanted to amend my previous play as he had done repeatedlv before he begged of me to go on on the plea that he believed he would construct a fine position from that point for analytical purposes or perhaps for a problem (for he was also a composer). He then deliberated on each move as if it were a match game, and if anyone had came into the room he must have thought we were playing a real hard fight. After some more moves the position resolved itself into an ending in which he had a decisive advantage and I agreed ultimately not to go on further. On another occasion shortly after that another opening was made the subject of one experiment and the same story almost exactly repeated itself. Great was, however, my surprise when about six months later I saw two games published which were alleged to have been played between Deacon and myself in the Dutch Chess journal Sissa. They comprised the opening moves in the two "novelties" which were the subject of our investigation, but almost all the rest (and I am certain about the concluding six or eight moves on each side) was entirely a new and imaginary fabrication Mr. Deacon was at the time when I first saw the games in Belgium, where he regularlv resided for several months during the year. On his return to England I remonstrated with him about the two so-called games, and I gave him a bit of my mind on the subject personally, but I did not proceed further in the matter for Deacon, though a so-called "gentleman" on account of his independent means, was already well known in London as a sort of Chess crank who tried to "correct fortune" as regards his Chess reputation by mean deceptions. But some time afterward it also came out that he had played similiar tricks on Signor Dubois and also to Mr. Blackburne and the Rev. J. Owen, and especially the latter gentleman threatened to take action against Deacon at the St. Georges Chess Club, of which both were members. Deacon then disappeared and retreated to his Belgian refuge. He was never seen in London again, and about a year afterward his death was announced. Judging from that I have no doubt that Morphy was entrapped to answer some analytical questions and to investigate some suggestions of Deacon over the board. What Colonel Deacon saw was nothing more than experimenting, in the course of which Morphy most probably had given back moves, as I did subsequently. Some variations which emanated from those trials may have formed the foundation for the manufacture of the games which Deacon claimed to have played against Morphy, but in all probability part of the middle and the end was entirely imaginary and never occurred at all, even during the experiments, as was the case in the two above described games which Deacon alleged to have played against myself.