PREFACE TO THE DE FLUXU ET REFLUXU MARIS. BY ROBERT LESLIE ELLIS. It was a natural result of the progress of maritime discovery in the sixteenth century, that much was thought and written on the subject of the tides. The reports continually brought home touching the ebb and flow of the sea on far distant shores, not only excited curiosity, but also showed how little the philosophers of antiquity had known of the phenomena which they attempted to explain. Men who dwelt on the shores of an inland sea, and whose range of observation scarcely extended beyond the Pillars of Hercules, were in truth not likely to recognise any of the general laws by which these phenomena are governed. Their authority accordingly in this matter was of necessity set aside; and a number of hypotheses were proposed in order to explain the newly discovered facts. Of these speculations an interesting account is given in the twenty-eighth book of the Pancosmia of Patricius. It is not, however, complete; no mention being made of the hypothesis of Casalpinus, which is in itself a curious one, and which clearly suggested to Galileo his own explanation of the cause of the tides. Otto Casmann, the preface to whose Problemata Marina is dated in 1596, gives a good deal of information on the same subject, some of which however seems to be simply copied from Patricius; but he mentions Casalpinus, whom, as I have said, Patricius omits. Patricius, it may be remarked, is a scrupulously orthodox philosopher, and dedicates his work to Gregory XIV. with many expressions of reverence and submission. It is perhaps on this account that he has said nothing of Casalpinus, whose works were "improbata lectionis" and who seeks to explain the tides, and also certain astronomical phenomena, by denying the orthodox doctrine of the earth's immobility. The earliest modern writer whom Patricius mentions is Frederick Chrysogonus, whose work on the tides must have been published in 1527. To his account of the phenomena little, according to Patricius, was added by subsequent writers; nor are his statements contradicted by the reports of seafaring men, who however mention certain matters of detail which he had omitted. Of seamen Patricius particularly mentions Peter of Medina and Nicolaus Sagrus, the latter with especial commendation. From Sagrus (but probably through Patricius) Bacon derived some of the statements of the following tract; those, namely, which relate to the progress of the tide-wave from the Straits of Gibraltar to Gravelines. On the day of new moon, according to Sagrus, there is high water along the coast from Tarifa to Rota at an hour and a half after midnight. After |