the great agent
...Thoreau's Journal: 03-Oct-1859
It is somewhat cooler and more autumnal. A great many leaves have fallen and the trees begin to look thin. You incline to sit in a sunny and sheltered place. This season, the fall, which we have now entered on, commenced, I may say, as long ago as when the first frost was seen and felt in low ground in August. From that time, even, the year has been gradually winding up its accounts. Cold, methinks, has been the great agent which has checked the growth of plants, condensed their energies, and caused their fruits to ripen, in September especially. Perchance man never ripens within the tropics.