Each one was separated by a slender thread, and followed the motion of its balloon. If they met a tree or a bush, they landed upon it; if not, coming close to the earth, they ran along and were lost in the verdure. If I approached them too quickly or made a noise, they remounted rapidly by their threads and went to disembark somewhere else.
I also examined some of the flakes. They were all shining white mats, appearing as if they had been washed. Several contained wings and feet of flies, fragments of the case of little coleoptera, and other remnants of their aerial festivities.
This encounter was for me a revelation. I knew where the spiders, whom I had seen disappear so brusquely, took refuge, and, however rash my judgment may appear, I felt assured I had solved an interesting problem.
But to establish seriously and give to science an opinion so new and original as that the atmosphere may be peopled with spiders, I soon felt that more proof was necessary in order to sit down calmly under my personal conviction. So I concluded I should not be doing too much if I added to the verification of their descent that of their ascension, and could surprise them in this new migration. I waited, therefore, impatiently for the spring.
But that spring, and for five or six that followed it, great was my disappointment; for, though I perceived several isolated ascensions, yet nothing in the proportion I had imagined or that could justify my hypothesis. I began then to doubt seriously my success, when an incident occurred that relieved my embarrassment, and proved how trifling sometimes are the causes which lift the veil from nature. I was looking straight upward, but sitting close to the earth, and so as to be able as much as possible to exclude the sun from my eyes. And here, by the way, a fact is made palpable, by no means microscopic, but which has escaped so long not merely the observation of the crowd of vulgar observers, but of those even who are wide awake and study carefully; namely, that it is not necessary to carry one's nose always in the air, if I may so express myself, to examine closely, to investigate, or to render a faithful account of phenomena.
On looking upward—as an ascension only takes place on very beautiful days, succeeding generally to bad weather—spiders cannot be distinguished from the multitude of other insects which fill the air. But if, on a beautiful day, mild, calm, and brilliant in sunlight, succeeding as nearly as possible to a rain warm with the south wind, at about nine or ten o'clock in the morning, a post is chosen on an eminence of a meadow or an avenue, and there, as near the ground as may be, and crouching low, the observer will look horizontally, he will perceive a series of fire-works, formed of innumerable threads launched from every direction and inclined toward the sky. This is the prelude. Soon the spiders detach themselves and mount slowly by their threads. The most conspicuous are the thomises bufo, because they are the largest, and because they only ascend with an entire bundle of threads, which gives them the appearance of small comets.
Thus have I decided
1st. That there is not only one ascension every year, but several, at least partial ones; that they do not always take place in spring, but often in the autumn, and sometimes even in the winter; and in general, from the descent which has taken place in the beginning of autumn until the definitive ascension in the spring, there are but few favorable days of which the spiders do not profit to make an aerial journey, or at least to throw out a large number of threads. Thus, in the Beaujolais, where I have lived for several years, there were partial ascensions on the 1st, the 19th, and the 28th of November, 1864; the 21st, the 23d, and especially the 25th of October, the 9th of November, and the 6th of December, 1865. In 1866, the 18th and the 30th of January, the 3d of February, the 3d, 14th, and 31st of October, and the 17th of December. In 1867, the 10th of February, ... the last, however, less considerable than might have been predicted by the beauty of the day. The day previous was so mild, though cloudy, that many of the spiders may have embarked incognito. Many, also, may not have judged it a propos to fly away, for a great number still remained on the ground. I forgot to observe the temperature of all the days I have noted. The director of the Normal School of Villefranche having had the kindness to show me the meteorological register which he had kept with great care, I was able to prove that in calm weather only ten or twelve degrees of heat were necessary to induce them to mount upward. The least exposed begin; then immediately the others, so soon as the heat reaches them; but after three or four o'clock in the afternoon no more ascensions are perceived, unless they are provoked; and this does not always succeed,