WINTER, SPRING, SUMMER, AUTUMN. The astronomical meaning of these words is derived from the considerations in SEASONS, and we are told and taught that winter begins at the winter solstice, spring at the vernal equinox, summer at the summer solstice, and autumn at the autumnal equinox. That is, according to the best authorities, it Is spring from the middle of March to the middle of June, summer from thence to the middle of September, autumn from thence to the middle of December, and winter from thence to the middle of March again. At the same time the poets and the farmers, who have a much better right than the astronomers to settle the meaning of these terms for common use, agree in placing the rise of vegetation, the pairing of birds, and the first appearance of flowers in the spring : the hay harvest and the ripening of all the earlier (nits in summer ; the grain harvest, the later fruits, and the fall of the leaves in autumn ; and the heavier frosts, snow, and ice, in winter.
It is impossible to fix a common commencement of the seasons even for the parte of the earth which lie between the Arctic circle and the tropic, which are all that need be considered ; for the polar and inter tropical regions have each a set of seasons of their own. But this we may safely say. that the agricultural and poetical seasons are earlier than the astronomical ones. All that distinguishes spring from winter
begins to take place before the vernal equinox, all that distinguishes summer from spring before the summer solstice, and so on. Most certainly it will be found that the greatest intensity of the several seasons happens, one year with another, at a period not long after the astronomical phenomenon at which the season is said to commence.
'When the year is divided only into summer and winter without further subdivision, it is then an exact division to say that the two halves begin and end with the equinoxes. But here the principal phenomena, the solstices, on approach to which heat and cold depend, are in the middle of the halves. If we were to divide the year into four seasons, during which the earth should receive from the sun the greatest and least portion of heat in two of them, and intermediate portions In the other two, the four astronomical commencements should be made the middle points of these seasons. The consideration in SEASONS will easily make it appear why, for the same reason as the greatest heat is after the longest day, the middle of the agricultural seasons should fall after the astronomical point of separation.