Mankind usually judge of a literary composition by its intrinsic merit, without taking into consideration the age of the author, the celerity with which it was composed, or the various circumstances under which it was written; and in this, perhaps, they act not unjustly, since their business is with the work, and not with the qualities of the author. But were such things to be taken into view, it should be remembered, that these Memoirs were hastily drawn up during the tumult and anxiety of campaigns, and were jotted down from day to day, without care or premeditation. “Ceteri,” says Hirtius, the companion of Cæsar’s expeditions, and the continuator of his Commentaries,—“Ceteri quam bene atque emendate; nos etiam quam facile atque celeriter eos perscripserit scimus.” The Commentaries, _De Bello Gallico_, and _De Bello Civili_, are the only productions of Cæsar which remain to us. Several ancient writers speak of his _Ephemeris_, or Diary; but it has been doubted whether the work, so termed by Plutarch, Servius, Symmachus, and several others, be the same book as the Commentaries, or a totally different production. The former opinion is adopted by Fabricius, who thinks that _Ephemeris_, or _Ephemerides_, is only another name for the Commentaries, which in fact may be considered as having been written in the manner and form of a diary. He acknowledges, that several passages, cited by Servius, as taken from these _Ephemerides_, are not now to be found in the Commentaries; but then he maintains that there are evidently defects (_lacunæ_) in the latter work; and he conjectures that the words quoted by Servius are part of the lost passages of the Commentaries. This opinion is followed by Vossius, who cites a sort of Colophon at the end of one of the oldest MSS. of the Commentaries which he thinks decisive of the question, as it shows that the term _Ephemeris_ was currently applied to them.—“C. J. Cæsaris, P. M. Ephemeris rerum Gestarum Belli Gallici, Lib. VIII. explicit feliciter.” Bayle, in his Dictionary, has supported the opposite theory. He believes the _Ephemeris_ to have been a journal of the author’s life. He admits, that a passage which Plutarch quotes as from the _Ephemeris_, occurs also in the fourth book of the Commentaries; but then he maintains, that it was impossible for Cæsar not to have frequently mentioned the same thing in his Commentaries and Journal, and he thinks, that had Plutarch meant to allude to the former, he would have called them, not _Ephemeris_, but ὑπομνηματα as Strabo has termed them. Besides, Polyænus mentions divers warlike stratagems, as recorded by Cæsar, which are not contained in the Commentaries, and which, therefore, could have been explained only in the separate work _Ephemeris_.