XXXIV. Experiments and observations made in Britain, in order to obtain a rule for measuring heights with the barometer

INTRODUCTION. In philosophical inquiries of every kind, where any point is to be ascertained by experiments, these cannot be repeated too often, nor varied too much, in order to obtain the truth: for even when the utmost precaution hath been used, and the greatest pains have been taken, it rarely happens, that they agree so exactly, as to leave no room for doubt. Were it possible at all times, to have experiments made in circumstances perfectly familiar, a considerable degree of consistency might naturally be expected among the results, whereof the mean would determine the point in question; but different men, making use of different instruments, have different modes of conducting their operations, each pursuing the tract that seems to him the most likely to insure success. Hence it is that a variety of results arise, and that things sometimes appear contradictory, or at least present themselves under new forms, difficult at first sight to be accounted for, and therefore apt to mislead, till by a farther investigation of the matter, the true causes are discovered. Even irregularities of this sort are worthy of being communicated, that others may know what hath happened before, and what, in like cases, they may expect to meet with, in the course of their future inquiries. Improvements of ever kind advance by slow degrees; and it is not until things have been viewed in every possible light, that the errors, even of our own experiments, are discovered, the points in question ultimately ascertained, and the branch of philosophy depending upon them, gradually brought nearer to perfection.