Physicist, born of Quaker parentage at Milverton, Somerset, studied medicine at London, Edinburgh, Göttingen, and Cambridge, and started as doctor in London in 1800, but devoted himself to scientific research, and in 1801 became professor of Natural Philosophy to the Royal Institution. His “Lectures” (1807) expounded the doctrine of interference, which established the undulatory theory of light. He was secretary to the Royal Society, and did valuable work in insurance, hæmodynamics, and Egyptology.

Personal

  Dined at the Athenæum. Hudson Gurney asked me to dine with him. He was low spirited. His friend, Dr. Young, is dying. Gurney speaks of him as a very great man, the most learned physician and greatest mathematician of his age, and the first discoverer of the clue to the Egyptian hieroglyphics. Calling on him a few days ago, Gurney found him busy about his Egyptian Dictionary, though very ill. He is aware of his state, but that makes him most anxious to finish his work. “I would not,” he said to Gurney, “live a single idle day.”

  Dr. Young was a man, in all the relations of life, upright, kind-hearted, blameless. His domestic virtues were as exemplary as his talents were great. He was entirely free from either envy or jealousy, and the assistance which he gave to others engaged in the same lines of research with himself, was constant and unbounded. His morality through life had been pure, though unostentatious. His religious sentiments were by himself stated to be liberal, though orthodox. He had extensively studied the Scriptures, of which the precepts were deeply impressed upon his mind from his earliest years; and he evidenced the faith which he professed, in an unbending course of usefulness and rectitude.

  I have not dwelt too long on the task imposed on me, if I have brought out, as I wished to do, the importance and novelty of the admirable law of interferences. Young is now placed before your eyes as one of the most illustrious men of science in whom England may justly take pride. Your thoughts, anticipating my words, may perhaps receive already, in the recital of the just honours shown to the author of so beautiful a discovery, the peroration of this historical notice. These anticipations, I regret to say, will not be realized. The death of Young has in his own country created very little sensation. The doors of Westminster Abbey, so easily accessible to titled mediocrity, remained shut upon a man of genius, who was not even a baronet. It was in the village of Farnborough, in the modest tomb of the family of his wife, that the remains of Thomas Young were deposited. The indifference of the English nation for those scientific labours which ought to add so much to its glory, is a rare anomaly, of which it would be curious to trace the causes. I should be wanting in frankness, I should be the panegyrist, not the historian, if I did not avow, that in general Young did not sufficiently accommodate himself to the capacity of his readers; that the greater part of the writings for which the sciences are indebted to him, are justly chargeable with a certain obscurity.

  Although Westminster Abbey does not hold his dust, Dean Buckland allowed Young’s devoted widow to place within its famous walls a profile medallion of him executed by Chantrey, and beneath it a slab containing an inscription written by his life-long friend Hudson Gurney. When we consider the grandeur of his genius, the multifarious greatness of his works, the simplicity and sublimity of his character, we are amazed at the indifference of mankind, which has suffered his name to rest in comparative obscurity.

General

  Such is the beautiful theory of Fresnel and Young; for we must not, in our regard for one great name, forget the justice which is due to the other; and to separate them and assign to each his share would be as impracticable as invidious, so intimately are they blended together throughout every part of this system,—early, acute, and pregnant suggestion characterizing the one, and maturity of thought, fullness of systematic development and decisive experimental illustration equally distinguishing the other.

  At the mention of Dr. Young’s name the historian must pause. None of our countrymen has approached more nearly the character of the celebrated Dr. Brook Taylor. Possessing the same ingenuity, extensive learning, varied accomplishments, and profound science, he combined likewise a concise, hard, and sometimes obscure, mode of stating his reasonings and calculations.

  It may safely be affirmed that no philologer ever before made such a discovery in science as the law of interference, and that no natural philosopher ever made such a step in the interpretation of a lost tongue as the formation (up to a certain point) of an Egyptian alphabet. We cannot close this imperfect sketch of one of the greatest ornaments of our age and nation, without adding that in private life Dr. Young was exemplary, endued with warm affections, philosophic moderation, and high moral and religious principles…. Dr. Young’s philosophical character approached in many important particulars to that of Newton. With much of the inventive fire of Davy and of the reasoning sagacity of Wollaston, he combined an amount of acquired learning, and a versatility in its application, far superior to both.

  Young’s own style of writing, if not idiomatic, was singularly pure: he had studied very carefully the principles of grammar, and one of his earliest essays in the Leptologist was in illustration of them: his sentences are usually short: he chooses the most simple words which will express his meaning: he rarely attempts to form carefully balanced periods, and never resorts to figurative expressions when those which are direct and immediate will answer his purpose: he was as little disposed to admire and imitate the poetical prose of Schiller in history as of Davy in philosophy, and was apt to regard them both as almost equally misplaced…. If we refer to his other scientific works, embracing so wide a range of subjects, and some of them—more especially his essays on the tides and the cohesion of fluids—so remarkable for the boldness and originality of their treatment, we shall find that they were rarely read and never appreciated by his contemporaries, and even now are neither sufficiently known nor adequately valued: whilst if justice was awarded more promptly and in more liberal measure by his own countrymen to his hieroglyphical labours, these also were singularly unfortunate, as far as concerned the general diffusion of his fame, by coming into collision with adverse claims which were most unfairly and unscrupulously urged in his own age, and not much less so by some distinguished writers in very recent times. The great variety also of his titles to commemoration as a classical scholar and archæologist, a medical writer, an optician, a mathematician, or a physical philosopher, increases the difficulty of judging his relative rank amongst men of celebrity, whether they were his contemporaries or not: for the position which he might not venture to claim in virtue of his contributions to any single department of human knowledge, might be readily conceded to him when his combined labours were taken into consideration.

  There is, perhaps, no name contemporary with that of Dr. Young, which will hold a higher place in the annals of British science and literature. In the various fields of natural philosophy, medicine, and archæology, he acquired a high reputation; and if he had devoted all his faculties to any one of these departments of knowledge, he would doubtless have attained to a still higher place in the temple of science. At an early period of his life Dr. Young was an accurate classical scholar. He was perfectly familiar with the principal languages of Europe. He was well versed in mathematics, and almost every department of natural philosophy and natural history. His knowledge of medicine and anatomy was profound, and he possessed a very unusual share of those personal and ornamental accomplishments which are so highly valued in the intercourse of society.

  The most clear-thinking and far-seeing mechanical philosopher of the nineteenth century, and one of its most accomplished and profound scholars…. Some of the merits of his works have already been mentioned; but it may be added that they are remarkable above all for their highly philosophical spirit, and in particular by the constancy with which they keep in view the distinction between beings and actions,—a distinction so often lost sight of in crude theories of physics.

  He was, in short, one of those rare phenomena that disturb from time to time the speculations of theorists upon the limited range of the human intellect.

  Young lectured for two years at the Royal Institution, and he afterwards threw the lectures into a permanent form in a quarto volume of 750 pages, with 40 plates, and nearly 600 figures and maps. He also produced at the same time a second volume of the same magnitude, embracing his optical and other memoirs, and a most elaborate classed catalogue of works and papers, accompanied by notes, extracts, and calculations. For this colossal work Young was to receive 1,000l. His publisher however became bankrupt, and he never touched the money. His lectures constitute a monument of Young’s power almost equal to that of his original memoirs. They are replete with profound reflections and suggestions. In his eighth lecture, on “Collision,” the term energy, now in such constant use, was first introduced and defined. By it he was able to avoid, and enable us to avoid, the confusion which had crept into scientific literature by the incautious employment of the word force. Further, the theory now known as the Young-Helmholtz theory, which refers all the sensations of colour to three primary sensations—red, green, and violet—was clearly enunciated by Young in his thirty-seventh lecture, on “Physical Optics.” His views of the nature of heat were original and correct…. Young’s essay on the “Cohesion of Fluids” is to be ranked amongst the most important and difficult of his labours.

  May be styled, without exaggeration, the most learned, profound, variously accomplished scholar and man of science that has appeared in our age—perhaps in any age…. As a physician, a linguist, an archæologist, a mathematician, scholar, and philosopher in their most difficult and abstruse investigations, Thomas Young has added to almost every department of human knowledge that which will be remembered to after-times.

  The remarkable fact that Young, of whom Helmholtz says (Vorträge und Reden, vol. i, p. 279) that he came a generation too soon, remained scientifically unrecognised and popularly almost unknown to his countrymen, has been explained by his unfortunate manner of expression and the peculiar channels through which his labours were announced to the world. His frequently unintelligible style, his obscure and inelegant mathematics, the habitual incognito which he preserved, his modesty in replying to attacks, and his general want of method in enunciating his ideas, contrast very markedly with the writings of some of his rivals, especially in France, where the qualities of style, method, and elegance were highly developed, and where recognised organs existed for the publication of works of genius. The historian of thought, however, must not omit to state that several great names contributed, by the authority they commanded, to oppose Young’s claims to originality and renown.

  Young has been justly called “the founder of physiological optics.” He was the first to prove conclusively that the accommodation of the eye for vision at different distances was due to change of curvature of the crystalline lens. His opinion that the lens itself was muscular has, however, not been confirmed by more recent work. His memoir “On the Mechanism of the Eye” contained the first description and measurement of astigmatism, and a table of optical constants of the eye in close agreement with modern determinations. He first explained colour sensation as due to the presence in the retina of structures which respond to the three colours, red, green, and violet respectively, and colour blindness as due to the inability of one or more of these structures to respond normally to stimulus. Young’s theory has been supported and extended by Helmholtz; and although a rival theory due to Hering is regarded with favour by many physiologists, there are phenomena unfavourable to the theory. Of other contributions connected with his profession two of the most noteworthy are the Croonian lecture to the Royal Society “On the Functions of the Heart and Arteries,” in which the laws regulating the flow of blood through the body are clearly stated, and its predecessor, “Hydraulic Investigations,” on which it depends.