noon
`` What will you do then ? '' `` I shall only use my chronometer , '' replied Captain Nemo . `` If to-morrow , the 21st of March , the disc of the sun , allowing for refraction , is exactly cut by the northern horizon , it will show that I am at the South Pole . '' `` Just so , '' said I. `` But this statement is not mathematically correct , because the equinox does not necessarily begin at noon . '' `` Very likely , sir ; but the error will not be a hundred yards and we do not want more . Till to-morrow , then ! '' Captain Nemo returned on board .