To live among friends is the primary essential of happiness.

Lord Kelvin's Replies to Addresses given on the Celebration of the Jubilee of his Professorship (June 15-17, 1896).
As quoted in :Lord Kelvin, Professor of Natural Philosophy in the University of Glasgow 1846-1899 (1899) by George F. Fitzgerald

An account of the celebrations on the occasion of Lord Kelvin's jubilee as a professor[babel.hathitrust.org]