Roscoe was a strong and consistent Liberal, a member of the Manchester School of Economists, and a devoted adherent of Mr. Gladstone, whom he followed in the Home Rule split. During the greater part of his parliamentary career, that is from 1886 to 1892, he sat on the Opposition benches, and had therefore comparatively little opportunity of accomplishing much in the way of legislative achievement. On questions involving scientific matters he could always secure the ear of the House, especially when these related to the comfort and well-being of its members, as when he took in hand the ventilation, lighting, and drainage of the Palace of Westminster. In 1888, and again in 1889, he introduced a Technical Education Bill, but it failed to reach the statute-book. In the latter year, however, the Government passed the Technical Instruction Act already referred to; this, although not wholly in accord with the views he had put forward, he gladly accepted as a satisfactory instalment. His efforts to pass an amending Bill in the following year met with no success. In 1891 the National Association for the Promotion of Technical Education, which was founded as a result of the Report of the Royal Commission of 1881, entrusted him with a Bill to remove certain disabilities which had been found to attend the working of the Act of 1889, and this he succeeded in carrying. It was one of the few private Bills of the session of 1891 that became law. He was frequently called upon to serve upon select committees, and in his last session he was Chairman of the Select Committee on Weights and Measures which led to Mr. Balfour’s Bill for legalizing the use of the metrical system in this country.