[My father was appointed, in 1816, a member of the Army Medical Board, and it became necessary for him to reside in London. He and my mother accordingly wished farewell to Scotland, and proceeded to take up their residence in Hanover Square. My mother preserved the following recollections of this journey:—

On our way we stopped a day at Birmingham, on purpose to see Watt and Boulton's manufactory of steam engines at Soho. Mr. Boulton showed us everything. The engines, some in action, although beautifully smooth, showed a power that was almost fearful. Since these early forms of the steam engine I have lived to see this all but omnipotent instrument change the locomotion of the whole civilized world by sea and by land.

Soon after our arrival in London we became acquainted with the illustrious family of the Herschels, through the kindness of our friend Professor Wallace, for it was by his arrangement that we spent a day with Sir William and Lady Herschel, at Slough. Nothing could exceed the kindness of Sir William. He made us examine his celebrated telescopes, and explained their mechanism; and he showed us the manuscripts which recorded the numerous astronomical discoveries he had made. They were all arranged in the most perfect order, as was also his musical library, for that great genius was an excellent musician. Unfortunately, his sister, Miss Caroline Herschel, who shared in the talents of the family, was abroad, but his son, afterwards Sir John, my dear friend for many years, was at home, quite a youth.