The weather is equally variable in Pennsylvania during the greatest part of the winter. The mercury fell from 37° to 4-1/2° below 0 in four and twenty hours, between the fourth and fifth of February, 1788. In this season nature seems to play at cross purposes. Heavy falls of snow are often succeeded in a few days by a general thaw, which frequently in a short time leaves no vestige of the snow. The rivers Delaware, Schuylkill, and Susquehannah have sometimes been frozen (so as to bear horses and carriages of all kinds) and thawed so as to be passable in boats, two or three times in the course of the same winter. The ice is formed for the most part in a gradual manner, and seldom till the water has been previously chilled by a fall of snow. Sometimes its production is more sudden. On the night of the 31st of December, 1764, the Delaware was completely frozen over between ten o'clock at night and eight the next morning, so as to bear the weight of a man. An unusual vapour like a fog was seen to rise from the water, in its passage from a fluid to a solid state. This account of the variableness of the weather in winter, does not apply to every part of Pennsylvania. There is a line about the 41° of the state, beyond which the winters are steady and regular, insomuch that the earth there is seldom without a covering of snow during the three winter months. In this line the climate of Pennsylvania forms a union with the climate of the eastern and northern states. The time in which frost and ice begin to show themselves in the neighbourhood of Philadelphia, is generally about the latter end of October or the beginning of November. But the intense cold seldom sets in till about the the 20th or 25th of December; hence the common saying, "as the day lengthens, the cold strengthens." The coldest weather is commonly in January. The navigation of the river Delaware, after being frozen, is seldom practicable for large vessels, before the first week in March. As in summer there are often days in which fires are agreeable, so there are sometimes days in winter in which they are disagreeable. Vegetation has been observed in all the winter months. Garlic was tasted in butter in January, 1781. The leaves of the willow, the blossoms of the peach tree, and the flowers of the dandelion and the crocus, were all seen in February, 1779; and I well recollect, when a school-boy, to have seen an apple orchard in full bloom, and small apples on many of the trees, in the month of December. A cold day in winter is often succeeded by a moderate evening. The coldest part of the four and twenty hours, is generally at the break of day.