Most of this correspondence concerns purely family affairs. However, the letters of Rear-Admiral Lord John Hay (died 1851) contain parliamentary, electoral and naval material; those of Lord Charles Edward Hay in 1851-1852 concern the Xhosa War in South Africa; and those of the 9th and 10th Marquesses of Tweeddale and the Earl of Gifford contain material relating to India - especially the Sikh wars, 1845-1849.