suppose that these disappointments fall upon the human race only, for other animated beings, as well as ourselves, are deceived in regard to them, although endowed with even a greater degree of sagacity upon these points than we are, from the fact of their very existence depending so materially upon them. Hence it is, that we sometimes see the summer birds killed by too late or too early cold, and the winter birds by heat coming out of the usual season. It is for this reason, that Virgil[414] has recommended us to study the courses of the planets, and has particularly warned us to watch the passage of the cold star Saturn. There are some who look upon the appearance of the butterfly as the surest sign of spring, because of the extreme delicacy of that insect. In this present year,[415] however, in which I am penning these lines, it has been remarked that the flights of butterflies have been killed three several times, by as many returns of the cold; while the foreign birds, which brought us by the sixth of the calends of February[416] every indication of an early spring, after that had to struggle against a winter of the greatest severity. In treating of these matters, we have to meet a twofold difficulty: first of all, we have to ascertain whether or not the celestial phænomena are regulated by certain laws, and then we have to seek how to reconcile those laws with apparent facts. We must, however, be more particularly careful to take into account the convexity of the earth, and the differences of situation in the localities upon the face of the globe; for hence it is, that the same constellation shows itself to different nations at different times, the result being, that its influence is by no means perceptible everywhere at the same moment. This difficulty has been considerably enhanced, too, by various authors, who, after making their observations in different localities, and indeed, in some instances, in the same locality, have yet given us varying or contradictory results.