Evelyn says in his Diary, 1676, September 10, "Dined with Mr. Flamsteed, the learned astrologer and mathematician, whom his Majesty had established in the new Observatory in Greenwich Park furnished with the choicest instruments. An honest sincere man."[512] This shows that in those days the term "astrologer" was synonymous with "astronomer." In an article on "Our Debt to Astronomy," by Prof. Russell Tracy Crawford (Berkeley Astronomical Department, California, U.S.A.), the following remarks occur:-- "Behind the artisan is a chemist, behind the chemist is a physicist, behind the physicist is a mathematician, and behind the mathematician is an astronomer." "Were it not for the data furnished by astronomers, commerce by sea would practically stop. The sailing-master on the high seas could not determine his position, nor in what direction to head his ship in order to reach a desired harbour. Think what this means in dollars and cents, and estimate it if you can. For this one service alone the science of astronomy is worth more in dollars and cents to the world in one week than has been expended upon it since the beginning of civilization. Do you think that Great Britain, for instance, would take in exchange an amount equal to its national debt for what astronomy gives it? I answer for you most emphatically, 'No.'" In his interesting book, _Reminiscences of an Astronomer_, Prof. Simon Newcomb says with reference to the calculations for the _Nautical Almanac_ (referred to in the above extract)-- "A more hopeless problem than this could not be presented to the ordinary human intellect. There are tens of thousands of men who could be successful in all the ordinary walks of life, hundreds who could wield empires, thousands who could gain wealth, for one who could take up this astronomical problem with any hope of success. The men who have done it are, therefore, in intellect the select few of the human race--an aristocracy ranking above all others in the scale of being. The astronomical ephemeris is the last outcome of their productive genius."