servation that the hours of high water correspond, speaking roughly, on the European and American coasts, Bacon quotes in the De Fluxu et Refluxu Maris no authority; but in the Novum Organum he ascribes it to Acosta and others. But it is very remarkable that Acosta does not say what Bacon makes him say, namely that the times of high water are the same on the coast of Florida and that of Europe, and that he does say what Bacon admits would be fatal to his theory, namely that there is high water at the same time in the Atlantic and Pacific oceans. In his Natural History of the Indies, iii. 14., he speaks of the tides, and of the two theories by which they had been explained. There are some, he says, who affirm that the ebb and flow of the sea resembles a caldron of water moved to and fro, the water rising on one side when it falls on the other, and reciprocally; while others liken it to the boiling over of a pot, which rises and falls on all sides The second view is in his judgment the true one. He says that he had inquired from a certain pilot, Hernandez Lamero,1 who had sailed through the Straits of Magellan about the year 1579, how he had found the tides there, and particularly if the tide of the South Sea or Pacific flowed when that of the North Sea or Atlantic ebbed, and vice versâ. Lamero made answer that it was not so, that both tides ebb and flow together, and that they meet about seventy leagues from the Atlantic and thirty from the South Sea. With this statement Acosta is altogether satisfied; and so far from trying to compare the time of high water on the opposite shores of the Atlantic, he remarks that but for the Straits of Magellan it would be impossible

at once.

1 See Acosta, iii. 11.

to determine experimentally which of the two theories he has mentioned is the true one; as only angels could make observations on both sides of the ocean at once, the eyes of men not reaching far enough to do so, and the distance being too great to be crossed by man in the time of a single tide.

DE FLUXU ET REFLUXU MARIS.

CONTEMPLATIO de causis fluxus et refluxus maris, ab antiquis tentata et deinde omissa, junioribus repetita, et tamen varietate opinionum magis labefactata quam discussa, vulgo levi conjectura refertur ad lunam, ob consensum nonnullum motus ejusdem cum motu lunæ. Attamen diligentius perscrutanti vestigia quædam veritatis se ostendunt, quæ ad certiora deducere possint. Itaque ne confusius agatur, primo distinguendi sunt motus maris, qui licet satis inconsiderate multiplicentur a nonnullis, inveniuntur revera tantum quinque; quorum unus tanquam anomalus est, reliqui constantes. Primus ponatur inotus ille vagus et varius (quos appellant) currentium. Secundus motus magnus oceani sexhorarius, per quem aquæ ad littora accedunt et recedunt alternatim bis in die, non exacte, sed cum differentia tali quæ periodum constituat menstruam. Tertius motus ipse menstruus, qui nil aliud est quam restitutio motus (ejus quem diximus) diurni ad eadem tempora. Quartus motus semimenstruus, per quem fluxus habent incrementa in noviluniis et pleniluniis, magis quam in dimidiis. Quintus motus semestris, per quem fluxus habent incrementa auctiora et insignia in æquinoctiis. Atque de secundo illo motu magno oceani sexhorario sive diurno, nobis in

præsentia sermo est præcipue et ex intentione; de reliquis solummodo in transitu, et quatenus faciant ad hujusce motus explicationem. Primo igitur, quod ad motum currentium attinet, dubium non est quin pro eo ac aquæ vel ab angustiis premuntur, vel a liberis spatiis laxantur, vel in magis declivia festinant ac veluti effunduntur, vel in eminentiora incurrunt ac inscendunt, vel fundo labuntur æquabili, vel fundi sulcis et inæqualitatibus perturbantur, vel in alios currentes incidunt atque cum illis se miscent et compatiuntur, vel etiam a ventis agitantur, præsertim anniversariis sive statariis, qui sub anni certas tempestates redeunt, aquas ex his et similibus causis impetus et gurgites suos variare, tam consecutione ipsius motus atque latione quam velocitate sive mensura motus, atque inde constituere eos quos vocant currentes. Itaque in maribus, tum profunditas fossa sive canalis atque interpositæ voragines et rupes submarinæ, tum curvitates littorum, et terrarum prominentiæ, sinus, fauces, insulæ multis modis locatæ, et similia, plurima possunt, atque agunt prorsus aquas earumque meatus et gurgites in omnes partes, et versus orientem et versus occidentem, austrum versus similiter et septentriones, atque quaquaversum, prout obices illi aut spatia libera et declivia sita sint et invicem configurentur. Segregetur igitur motus iste aquarum particularis et quasi fortuitus, ne forte ille in inquisitione quam prosequimur obturbet. Neminem enim par est constituere et fundare abnegationem eorum quæ mox dicentur de motibus oceani naturalibus et catholicis, opponendo motum istum currentium, veluti cum thesibus illis minime convenientem. Sunt enim currentes meræ compressiones aquarum, aut liberationes a compres