Sentence:  If you question a seaman on the subject, whether mere coaster or circumnavigator, he will tell you that in a snow-storm, because of its constant eddyings and <WSD>gyrations</WSD>, frequent trimming of sails is more necessary than in any other gale... 
Meaning of the word marked with <WSD> tags:  The act of turning or whirling, as around a fixed center; a circular or spiral motion; motion about an axis; rotation; revolution.