XVIII. But after all this was ascertained, they found, that by trusting the bringing of ships into barr’d or tide harbours, to the mere combination of the before-nam’d observations, they fell into very dangerous errors; for that there are two other variations, which are very considerable, and especially one of them, and which can’t be comprehended under any general rule whatsoever; the one is with respect to the time of full sea; and the other, regards the quantum of rise of the water. The time of full sea varies at different ports, even under the same meridian, and does not happen in all of them at the same hour. They vary also with respect to the magnitude of them, because there is an enormous difference in the height they flow at some ports, to what they do at others, for the water will rise more than ten fathoms upon some coasts, and not above a few feet on others, and in others again, the rise is hardly perceptible. SECT. V. XIX. If the rules deduced from experimental observations are so fallible, that it is absolutely necessary in order to avoid all error, to pursue the thread of them so scrupulously, that reason should not venture to advance a step, without the light of an experiment appropriated to the business it is in search of; I say, if these rules are not to be relied on, what confidence can we place in those maxims, which derive their origin from our arbitrary ideas? XX. Nature conforms to, and is governed by the idea of its great artificer, not by that of man; and it is strange temerity in man, to presume he can comprehend the idea of such an artificer. I have sometimes thought, that if we were told, that there were numbers of those luminous bodies in the heavens which we call stars, although we could not see them, every one would imagine, such a disposition and collocation of them in the sphere, as best suited his own fancy. One would conceive them distributed into various regular sets of figures, such as triangular, hexangular, circular, &c. which formed so many different constellations; another, that they were composed of a beautiful suit, of well ranged and harmonious groups; another, that they were disposed after the manner of flowers, which he had seen growing in parterres in some garden; another, that they were formed in such a position, as resembled the shape of various images, either mystic or natural. In fact, there would be no body, that would not attribute to them some most beautiful resemblance, or imitation, of those things which he had ever seen, that seemed most pleasing to him, either in art, or nature. Notwithstanding which, they would all deceive themselves, and be greatly surprised, upon the firmament afterwards being displayed to their view, to find the stars placed and ranged in a position, quite different and distinct from all they had imagined. SECT. VI.