determination of latitude

On page 437 of Turner FYM, there is a section titled ‘How is the Latitude of a Place Determined?’. There follows the following statement: “It can be determined by measuring the greatest angle of elevation of the sun on the day of the spring or autumn equinox.” The text then proceeds to determine that the latitude of Melbourne, Australia, is 38 degrees South.
Also, here is the link to the Wikipedia article on latitude.