Just in the same manner as the locust-eating thrush accompanies the locusts, so the coccinellæ seem to pursue the aphides: whether the latter cross the sea is not known; but the coccinellæ certainly do, as they have often alighted upon vessels at sea.
17th.—I have just read a passage in Kalm’s Travels in North America, which seems, in some degree, to confirm that opinion of Dr. Walker’s, about the flowering time of foreign plants, which my uncle mentioned last week.
“The crab trees opened their flowers yesterday; whereas, the cultivated apple trees which were brought from Europe, had already lost theirs. The wild cherry trees did not flower till May 12th; but the European ones had opened theirs by the 24th of April. The walnuts of this country had neither leaves nor flowers, when the European kinds had both. Hence it appears that the trees brought over from Europe, of the same kind with the wild trees of North America, flower much sooner than the latter. I cannot say the cause of this forwardness, unless it be that they bring forth their blossoms as soon as they get the degree of warmth to which they have been used in their own country: it almost seems as if the native trees of this country are directed, by experience, not to trust to the first warmth of spring, while the flowers of the European trees are often killed by the late frosts.”
I read this passage to my uncle, and asked him if these plants did not seem almost to have instinct?
He smiled, and said, “I can give you another remarkable fact. The wild potatoe, from Valparaiso, flowers in the garden of the Horticultural Society in October, which you know is the spring of South America. All these curious circumstances are manifest proofs of the wisdom of Providence, who has impressed on plants and animals the habits proper to the situation in which he placed them.”
I afterwards asked my uncle if the American fruits were very late in ripening, as the blossoms are so long kept back by winter.
“No,” he said, “the summer is very warm, though the winter is long and severe; and, as animals become more sensible to heat, after being previously exposed to cold,—for the same reason that your hands glow on coming into the house after having been rubbed with snow—so vegetables seem to be excited to a greater degree of energy by the previous intense cold. Vines, in grape-houses which have been exposed to the open winter air, become forwarder and more vigorous than those which have been kept shut up in the house. In the northern latitudes, after the dissolution of the snow, the rapidity of vegetation would astonish you.
“Clarke mentions, in his travels in Scandinavia, that it is by no means uncommon for barley to be reaped in six weeks after it has been sown; for in summer the sun is so long above the horizon there, that there is scarcely any intermission of the warmth of the soil during the night.”
19th, Sunday.—“While we are engaged in considering the history of Moses,” said my uncle this morning, “I think we should dwell a little on a very striking part of his character, in order to imitate it, though, indeed, we can never be tried like him, in having the guidance of such a wayward and stiff-necked people. Bertha, guess to what quality I allude.”
“Perhaps to his meekness, which the Bible mentions as being remarkable,” I replied.