Page:Mathematical collections and translations, in two tomes - Salusbury (1661).djvu/435

 from East to West, yet nevertheless the different Position of the Shores may make part of the Water regurgitate, and return backwards: I grant it you, but it is necessary that you take notice my Simplicius, that where the Water upon that account returneth backwards, it doth so there perpetually; and where it runneth straight forwards, it runneth there alwayes in the same manner; for so the example of the Rivers shewes you. But in the case of the ebbing and flowing, you must finde and give us some reason why it doth in the self same place run one while one way, and another while another; Effects that being contrary & irregular, can never be deduced from any uniform and constant Cause: And this Argument, that overthrows the Hypothesis of the motion contributed to the Sea from the Heavens diurnal motion, doth also confute that Position of those who would admit the sole diurnal motion of the Earth, and believe that they are able with that alone to give a reason of the Flux and Reflux: Of which effect since it is irregular, the cause must of necessity be irregular and alterable.

.I have nothing to reply, neither of my own, by reason of the weakness of my understanding; nor of that of others, for that the Opinion is so new: But I could believe that if it were spread amongst the Schools, there would not want Phylosophers able to oppose it.

.Expect such an occasion; and we in the mean time if it seem good to Salviatus, will proceed forward.

.All that which hath been said hitherto, pertaineth to the diurnal period of the ebbing and flowing; of which we have in the first place demonstrated in general the primary and universal Cause, without which, no such effect would follow: passing to the particular Accidents, various, and in a certain sort irregular, that are observed therein: We have handled the secondary and concommitant Causes upon which they depend. Now follow the two other Periods, Monethly, and Annual, which do not bring with them new and different Accidents, other than those already considered in the diurnal Period; but they operate on the same Accidents, by rendring them greater and lesser in several parts of the Lunar Moneth, and in several times of the Solar Year; as if that the Moon and Sun did each conceive it self apart in operating and producing of those Effects; a thing that totally clasheth with my understanding, which seeing how that this of Seas is a local and sensible motion, made in an immense mass of Water, it cannot be brought to subscribe to Lights, to temperate Heats, to predominacies by occult Qualities, and to such like vain Imaginations, that are so far from being, or being possible to be Causes of the Tide; that on the con-