There is reason to believe that Gunter was the first to discover (in 1622 or 1625) that the magnetic needle does not retain the same declination in the same place at all times. By desire of James I he published in 1624 "The Description and Use of His Majesties Dials in Whitehall Garden", the only one of his works which has not been reprinted. He coined the terms cosine and cotangent, and he suggested to Henry Briggs, his friend and colleague, the use of the arithmetical complement (see Briggs "Arithmetica Logarithmica", cap. xv). His practical inventions are briefly noted below: