The Art of Computation; Designed to Teach Practical Methods of Reckoning with Accuracy and Rapidity (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1874 Excerpt: ...be on the meridian before mean noon when the sign is +, and after mean noon when it is--. The year is divided unequally into twelve months, which are, with the number of days in each, as follows: January. February March.. April May.... June....31 days. July 31 days..28 - August 31.31 September 30.30 October 31.31 November 30.30 December 31 Formerly the new year began upon the twentyfifth day of March, and was so reckoned in England until 1753. As the year contains 3651 days, it is common to reckon three years in every four as containing 365 days, and the fourth, always that which is a multiple of 4, as containing 366 days. The extra day is added to February, which thus has 29 days in years divisible by 4. As the year contains exactly 365d. 5h. 48m. 50sec, to reckon it 365 days occasions an error of 11m. lOsec. This in 400 years amounts to about three days; hence the even centuries, 1800, 1900, etc., are not considered leap years unless divisible by 400. A slight error still remains, which will be compensated by considering the year 3600 as a common year, though divisible by 400. These irregularities render difficult the construction of a perpetual calendar. Indeed, the reconciling of dates has been so imperfectly understood, that the landing of the Pilgrims at Plymouth Rock was celebrated for several years upon a day which was not an anniversary of the occasion. The Julian Calendar, which was in Catholic countries changed to the Augustan Calendar in 1583, prevailed in England till 1753, and is still used in Russia and other countries which are under the Greek church. Between these calendars there was a difference in 1583 of ten days, in 1753 of eleven days, and there is now a difference of twel...