On looking at the map of England it will be seen that from the extreme east coast (Lowestoft) to the extreme west coast (Land’s End) the country extends from Greenwich 1° 45′ on the East 5° 40′ 25″ on the West. Now, as the sun appears to travel from an easterly to a westerly direction each day, and takes four minutes to travel over one degree of longitude, it can be seen that it will take about 30 minutes to travel across the whole country, and the time of all places east of Greenwich is fast, whilst at others west the time is slow. For example, supposing a sundial in position at each of the following places, Lowestoft, Greenwich, and Land’s End, and it was noon at Lowestoft by the sundial, the time indicated at the moment by each dial would be as follows: Lowestoft, 12 o’clock; Greenwich, 7 minutes to 12; Land’s End, about 22¾ minutes to 12. But our watches would have given the time as 12 o’clock at all places at the same moment, so we see that something is required in the way of a table calculated for every day of the year, giving the variations daily between the sundial and the watch. The following table, called an “Equation Table,” gives the difference in minutes, and you will notice that the sundial and clock both agree on four occasions during the year: 15th April, 14th June, 1st September, 25th December. EQUATION TABLE. FAST MEANS THAT THE WATCH SHOULD BE FASTER THAN THE DIAL. SLOW, SLOWER. ════════════════╤════════════════╤════════════════╤════════════════ JAN. │ FEB. │ MARCH. │ APRIL. ────────────────┼────────────────┼────────────────┼──────────────── Days. Mins.│Days. Mins.│Days. Mins.│Days. Mins. 2 Fast 4│ 3 Fast 14│ 4 Fast 12│ 1 Fast 4 4 5│ 20 14│ 8 11│ 5 3 7 6│ 27 13│ 12 10│ 8 2 9 7│ │ 16 9│ 12 1 11 8│ │ 19 8│ 15 0 14 9│ │ 23 7│ 20 Slow 1 17 10│ │ 26 6│ 25 2 20 11│ │ 29 5│ 24 12│ │ │ 28 13│ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ ════════════════╧════════════════╧════════════════╧════════════════