The weather has been so astonishing the last few days one cannot realise it is the week, not of the shortest days, but of the shortest afternoons of the whole year. This sentence brought about a fearful coolness between me and my dear secretary, who asked for an explanation of the statement, and, when I tried to give it, failed to understand. We agreed to refer the matter to an authority that we both believed in. The next day brought the following reply: 'The explanation you require is, I think, hardly suited to "Pot-Pourri." I should ut it somehow thus: "that week in which the almanack tells us the days are growing shorter, though the sun sets at a later hour." Of course the afternoon does not grow longer. Noon is the moment at which the sun crosses the meridian, and it then attains its highest point for the day; and of course if it rises later, it also sets earlier. The apparent anomaly occurs thus - the solar day, which is measured from the time the sun crosses the meridian on one day to the time it does ditto on the next, is not of uniform length. The reasons - which you need not read - are: (1) The path of the sun does not lie in the equator, but in the ecliptic; (2) owing to the earth's orbit not being circular, its motion in the ecliptic is not uniform. Now it would manifestly be very uncomfortable to have days of varying length, therefore an imaginary sun has been invented which is supposed to behave in a decent and orderly fashion; the time by him is called "mean time," and is that shown by a watch. The time shown by the real sun is called "apparent time," and is that shown by a sun-dial. The difference between these two times is as much as sixteen minutes at certain seasons of the year. Now on the shortest day the sun crosses the meridian nearly two minutes before twelve o'clock. He was earlier the few days before, therefore his time of setting was earlier too. Suppose that on December 21st apparent noon is at 11.58 a.m. and the sun sets at 3.51 p.m., and on December 14th the apparent noon is at 11.55 a.m. and the sun sets at 3.49 p.m. Now the afternoon on December 14th is one minute longer than on December 21st (3 hours 54 minutes to 3 hours 53 minutes), and yet the sun has set two minutes earlier (by our watches).'