by Sir Harold Spencer Jones
SC.D., F.R.S.,
The Astronomer Royal
Navigation is both a science and an art whose development has been based upon the knowledge of many different types of person
The problems of navigation can be explained very simply, They are to determine the position of a ship or aircraft at a particular instant of time, and then, knowing the position, to determine the course that will bring the craft to a required position and to estimate its time of arrival.
At sea this problem was not solved till late in the eighteenth century. The founding of the Greenwich Observatory, the invention of the sextant, the compilation of the Almanac, and the invention of the marine chronometer were the most important contributions to the solution.
In the air fresh problems arise ... their solution being one of the most dramatic episodes in the recent war.