EARLY HISTORY OF THE NAUTICAL ALMANAC. 9 



an operation that the most scientific navigator could hardly be 

 expected to undertake. 



To remove this difficulty, Dr. Maskelyne proposed to the 

 Board of Longitude that the positions of the sun for noon, and 

 of the moon for noon and midnight, should be calculated for each 

 day by Mayer's tables, and that these positions, with other 

 astronomical information useful to the mariner, should be incor- 

 porated into a "Nautical Almanac," appearing one or more 

 years in advance. Dr. Maskelyne, who had just been appointed 

 Astronomer Eoyal, undertook the responsibility of its prepara- 

 tion, and he continued its superintendent till his death in 1811. 

 The first Almanac was published in 1766 for the following year, 

 in the preface of which he remarks that "the difficulty and 

 length of the necessary calculations seemed the only obstacles to 

 hinder Mayer's tables from becoming of general use ; to remove 

 which this ephemeris was made ; the mariner being hereby 

 relieved from the necessity of calculating the moon's place from 

 the tables, and afterwards computing the distance to seconds by 

 logarithms, which are the principal and only very delicate part 

 of the calendar ; so that the finding the longitude by the help of 

 the ephemeris is now in a manner reduced to the computation of 

 the time, an operation equal to that of an azimuth, and the cor- 

 rection of the distance on account of refraction and parallax." 



By these tables of Mayer, the power of calculating com- 

 paratively accurate positions of the sun and moon was much 

 facilitated, and so important was this considered by the Astro- 

 nomer Eoyal and the Board of Longitude, that, on the recom- 

 mendation of the latter, an Act of Parliament was passed 

 empowering the Government to award the munificent gratuity of 

 £3000 to Mayer's widow, and £300 to Euler, who had furnished 

 the theorems made use of by Mayer in the construction of the 

 theory. These tables were published at the expense of the 

 British Government in 1770, and a new edition, improved by 

 Charles Mason, appeared in 1787.* 



In the preparation of the initiatory volume of the ' ' Nautical 

 Almanac" for 1767, several persons were necessarily employed 

 on the calculations, raost of which was computed in duplicate by 



* Copies of both of these editions, formerly belonging to the "Rev. Malachy 

 Hitchins, are in my possession. 



