XXXVI EOTAL SOCIETY OF CANADA. 



The joint committee, appointed by the Canadian Institute and the Astronomical and Phj'sical 

 Society of Toronto, have the honour to report on that branch of the subject of time-reckoning spe- 

 cially referred to them. 



The unification of the reckoning of the day has long been under consideration. Sir John Herschell, 

 in his "Outlines of Astronomy," alluded to the advantages which would I'csult from bringing into 

 agreement the civil, the astronomical, and the nautical days. He pointed out that the adoption of 

 the civil day for astronomical purposes would but slightly inconvenience astronomers, and that in 

 a question which concerns all other classes of men, astronomers should resolve to act on general prin- 

 ciples and cheerfully submit to a small inconvenience in view of the far wider interests which would 

 be benefited. " Uniformity," he said, "in nomenclature and mode of reckoning in all matters relating 

 to time, space, weight, measu.-es, etc., is of such vast and paramount importance in every relation of . 

 life as to outweigh every considei-ation of technical convenience or custom." 



The civil day begins at midnight and ends at the midnight following. The astronomical day 

 begins at noon of the civil day and continues until the following noon. The nautical day concludes 

 at noon of the civil day, having commenced at the preceding noon. 



It is obvious that any given date extends over, or into, three different days. Take for example, 

 Wednesday, June 13th. By astronomical and nautical reckonings, only half of this date in each case 

 is on Wednesday; the first half of June 13, according to nautical reckoning, is on Tuesday, June 12, 

 while the second half of the same date (June 13th), according to astronomical reckoning, is on 

 Thursday, June 14th, civil time. 



In this we have the elements of confusion, and it is not surprising that the Washington Interna- 

 tional Conference of 1884 i-ecommended that the civil day should take the place of the astronomical 

 and nautical days for all purposes. The recommendations of the Washington Conference must be 

 held to carry weight, as this assemblj' comprised representatives of science from twenty-five nations 

 specially called together to consider questions of time-reckoning. Among them were astronomers 

 of world-wide fame, as well as men who held high rank as navigators. They were unanimous in 

 the opinion that as soon as practicable the astronomical and nautical days should be arranged every- 

 where to coincide with the civil day. 



The civil day is the reckoning used by the generality of mankind. It is the exact mean 

 between the astronomical and nautical days, and differs precisely twelve hours from both. To effect 

 a complete coincidence, it is only necessary to shift astronomical and nautical days each twelve 

 hours, and this shifting will bring both to the civil day. Many ships have already abandoned nau- 

 tical time and date their logs according to civil reckoning ; all ships would use the one reckoning 

 only, if the Nautical Almanac and Ephemerides genei'ally were arranged for civil time. There can 

 be no doubt whatever that the marine of all nations would benefit by the change. 



If we consider the subject simply in its relation to the Nautical Almanac and navigation, the 

 unification of time-reckoning would simplify the calculations of mariners and reduce the chances of 

 error. One correspondent (Dr. Johnson, of McGill Universitj^), points out very truly " that the 

 omission of even a single step in an oft-repeated process of calculation has an obvious advantage; 

 when the simplification removes at the same time that most dangerous source of error, an ambiguous 

 expression, it becomes a great gain." He says that the subject resolves itself unto a question of 

 practical utility, viz., what is the greatest good of the greatest number? The Nautical Almanac, as 

 its name implies, is for the use primarily of navigators, who are very numerous and yearly increasing. 

 Compared with the men who guide the floating tonnage of the world, astronomers are extremely few 

 in number, and astronomers as a class are skilled calculators; moreover, astronomers can make 

 their calculations under the most favourable circumstances, consequently with the least liability to 

 error, as they are removed from the disturbing influences to which seamen are frequently exposed. 



The joint committee considered it important to ascertain how far astronomers generally would 

 support the proposal which would practically abolish the astronomical day. On April 2l8t, 1893, a 



