DRUMMOND, Captain THOMAS, RE., was born at Edinburgh in 1797, and during his professional training at Woolwich and Chatham displayed high mathematical and mechanical abilities, with much aptitude for the application of scientific principles to practical affairs. In 1820, he was engaged by ad. Colby to assist in the trigonometrical survey of the United Kingdom. The incandescence of lime having been brought under his notice at a lecture on chemistry, the idea occurred to him that it might be advanta geously used on the survey to render distant objects visible: he accordingly made experi ments, which, with their results, and the first application of the Drummond light (q.v.) in Ireland, are described by him in the Philosophical Transactions for 1826. A heliostat (q.v.) of his invention, described in the same paper, has ever since been employed with success in the survey. Experiments which he made with the view of adapting his "Light" to light-houses, are detailed in the Philosophical Transactions for 1830. When exhibited at Purfleet, it was powerful enough to cast shadows at Blackwall, distant 10 miles. Practical difficulties, not yet overcome, prevented the fulfillment of his hopes in this direction; his attention having been diverted to political life, for which he soon proved himself to be eminently fit. As the head of a commission appointed by lord Grey's government to superintend the fixing of the boundaries of the boroughs under the pro visions of the reform bill, he performed most ably that laborious and important work. He next acted as private secretary to lord Althorp, chancellor of the exchequer; and finally, in 1835, went to Dublin with lord Mulgrave, as under-secretary for Ireland Here the knowledge of Irish character and feelings which he had acquired in the survey was of great advantage to him, and by his impartiality, sound judgment, conciliatory dis position, indefatigable energy, and hearty devotion to the work before him, he at once gained the confidence, and.affection pf the people: It was in a letter.written by him to
the magistrates of Tipperary on the 22d of May, 1838, that the memorable words occurred—" Property has its duties as well as its rights;" an aphorism which instantly flew over Ireland, and continues everywhere to exercise a wholesome influence. But it was perhaps as the head of a commission appointedin 1836 to report on a railway sys tem for Ireland, that D. rendered that country his greatest service by the admirable report which he had the main labor of producing, So far as the routes recommended have been followed, the expectations of the commissioners have been fulfilled or exceeded; and it is the opinion of good judges that it would have been well for Ireland had the carefully digested scheme been more fully adopted. By these multiplied labors, however, D.'s strength was overtasked, and he sank on the 15th of April, 1840, amidst the grief of the Irish people, and of his intimates in public life, who had hoped to see him rise to some of the highest offices in the state. A statue by Hogan was erected to his memory by public subscription, in the royal exchange at Dublin; and a memoir of his professional life (abridged in Knight's English Cyclopcedia of Biography, ii. 647) was published in 1841 by capt. Larcom, in the 4th volume of Papers on Subjects Connected with the Duties of the Corps of Royal Engineers.