THE CONQUEST OF TIME AND SPACE 



the course of the moon were by no means reliable, hence 

 theoretically excellent methods of determining longi- 

 tude by observation of that body proved quite unreliable 

 in practice. 



It was with the chief aim of bettering our knowledge 

 of the moon's course through long series of very accurate 

 observations that the Royal Observatory at Greenwich 

 was founded. Perhaps it was not unnatural under these 

 circumstances that certain of the Astronomers Royal 

 should have advocated the method of lunars as the 

 mainstay of the navigator. In particular Maskelyne, 

 who was in charge of the Observatory in the latter 

 part of the eighteenth century, was so convinced of the 

 rationality of this method that he was led to discredit 

 the achievements of Harrison's watches, and for a 

 long time to exert an antagonistic influence, which the 

 watchmaker resented bitterly and it would appear not 

 without some show of reason. 



Ultimately, however, the accuracy of the watch, 

 and its indispensableness in the perfected form of the 

 chronometer, having been fully demonstrated, the 

 method of lunars became practically obsolete and the 

 mariner was able to determine his longitude with the 

 aid of sextant, chronometer, and Nautical Almanac , by 

 means of direct observation of the altitude of the sun 

 by day and of sundry fixed stars by night, a much 

 simpler calculation sufl&cing than was required by the 

 older method. 



As the sun is the chief time-measurer, whose rate of 

 passage in a seeming circumnavigation of the heavens 

 is recorded by the dial of clock, watch, or chronometer, 



[32] 



