Advancing years and disappointed hopes caused no abatement in his interest in foreign affairs. The events of 1848 had been specially interesting to him; and at the close of that year he produced what Mr Reid well describes as ‘a striking and instructive’ pamphlet, entitled _A Letter to the Marquis of Lansdowne_. The author reviews the events of the year, and supports the thesis that ‘the Liberals of the Continent had not proved themselves unworthy of the sympathy of England.’ We have no room for an analysis of this masterly work, but we cannot refrain from quoting one remarkable passage in which he foreshadows French intervention in Italy. After describing measures by which Austria intended to make the Lombardo-Venetian kingdom a second Poland, he proceeds: ‘And France, whatever be her adventures in government, will not easily have so dulled her imagination or quelled her enthusiasm as to be unmoved by appeals to the deeds of Marengo and Lodi, and to suffer an expiring nation at her very door to cry in vain for help and protection, not against the restraints of an orderly authority, but against fierce invaders intent upon her absolute destruction’ (vol. i. p. 413). This pamphlet made a great sensation. In England it was received, for the most part, with dislike and apprehension. Carlyle was almost alone in praising it. ‘Tell him,’ he said, ‘it is the greatest thing he has yet done; earnest and grave, written in a large, tolerant, kind-hearted spirit, and, as far as I can see, saying all that is to be said on _that_ matter.’ But the strongest proof of the power of the pamphlet is the fact that the Austrians stopped the writer on the Hungarian frontier when travelling with his wife in 1851, as a person who could not breathe that revolutionary atmosphere without danger to the empire. In his later years foreign travel became almost a necessity to Lord Houghton; and as he had then fewer ties to bind him to England, his absences were more frequent and more prolonged. He travelled in France, no longer as an envoy without credentials, but for his private information, or to be the guest of Guizot and De Tocqueville; he became the friend of the accomplished Queen of Holland; he represented the Geographical Society at the opening of the Suez Canal; he made a triumphal progress through the United States; and only three years before his death he went again to Egypt and Greece.