# Popular Science Monthly/Volume 36/March 1890/Sketch of A. F. J. Plateau

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Antoine Ferdinand Joseph Plateau.
* SKETCH OF A. F. J. PLATEAU.
By SOPHIE BLEDSOE HERRICK.
ANTOINE FERDINAND JOSEPH PLATEAU was born in Brussels, October 14, 1801. He was brought up in the midst of artistic influences, his father having been a flower-painter of great talent. From his earliest childhood the boy exhibited not only remarkable ability, but clearly manifested the bent of his mind. When scarcely more than a baby he showed the greatest delight in some physical experiments which were made in his presence.
In the days when Plateau was a child, very little attention was paid to natural bent by parents in the selection of a life-work for their children. The idea of the hereditary transmission of occupation dominated all others. The boy, with no taste for art, was devoted at an early age by his father to the study of painting.
At fourteen years of age he became an orphan, and with his two sisters was left to the care of his uncle—M. Thirion, an advocate. Soon after this his health, which was never strong, showed signs of failure; and his uncle sent the children to a little village near Waterloo. It was upon the eve of the battle, and the villagers took refuge in the depths of the forest of Soignes, where for two days and nights they remained in the open air, sleeping at night before a great fire, and living upon potatoes which were baked in the cinders.
The boy seemed scarcely conscious of the violent detonations which shook the ground beneath them, he was so absorbed in his favorite pastime of catching butterflies. The panic over, the ​villagers went back to their homes, and Joseph and his sisters remained some time in the little village of Ohain.
As soon as his health was restored he returned to his art studies. Here he made such excellent progress that one evening Prince Frederick, the son of the king, who was visiting the establishment, was attracted by the boy's work. When he found that Joseph was an orphan, he said, "Well, from this moment I take you under my protection." Later, when M. Thirion wished to remind the prince of his promise, he was deterred by the boy's unwillingness to make any claim upon him.
Painting occupied Joseph by day, but in the evening and in his leisure moments his beloved physics employed all his time. With the aid of some young friends he organized soirées, the entertainment being experiments of his own devising, made with apparatus constructed by himself.
At sixteen years of age he entered the Athenæum at Brussels. He omitted certain studies, but in all that he undertook he distinguished himself by his enthusiastic progress. His masters became at once interested in their brilliant pupil. The friendship of Quetelet, which became stronger as time went on, proved of the greatest benefit to him in later life.
His school-life over, the subject of a profession presented itself for reconsideration. His uncle pressed upon the boy the study of law, as the noblest of all professions, and Joseph consented. In choosing art there had been no great sacrifice; he had been too young at that time to know his own mind; but he felt a strong antipathy to the law.
This dislike did not prevent honest and conscientious work in the pursuit of his legal studies; but the physical sciences held for him their old fascination, and he made the rather singular compromise of studying both law and physics, and doing himself credit in both alike. His faithful work had its reward at last: his uncle, seeing his determination, and at the same time his willingness to be guided, withdrew his opposition, and the young student gave himself up wholly to scientific pursuits.
The care of his younger sister now fell upon Plateau, and, pressed by the necessity to provide for them both, he accepted the professorship of elementary mathematics in the Athenæum at Liége. This was in 1827. In 1829 he received the degree of Doctor in Physical Sciences and Mathematics, and from that time he gave himself to original research.
During this year he devoted much time to experimenting upon various points in regard to vision, to the persistence of impressions upon the retina, subjective color, etc. On one occasion, to determine some point, he looked at the sun for twenty-five seconds with the naked eye. For many days after this hazardous ​experiment his eyes were strongly affected, bnt he did not suspect that he had done them a permanent injury. This experiment undoubtedly laid the foundations of that disease which twelve years later brought on total blindness.
After being forced to resign his work, in 1830, he again resumed it at Brussels. In 1835 Quetelet urged Plateau to apply for the professorship of experimental science in the University of Ghent. The young savant refused at first to offer himself as candidate for a position in the first institution in his native land, pleading youth and inexperience; but later his scruples were overcome, and he received the appointment to the chair.
As soon as he began his work in Ghent, he found the collections of the university very poor and meager. He gave himself at once to the work of remedying this deficiency. In order to inform himself, he visited and examined minutely the most celebrated collections in England, France, and Germany. He addressed the Government and the inspector of the university, and pleaded his case so well that in the end—though it was only after long and wearisome labor—he succeeded in securing one of the finest physical cabinets in existence to the University of Ghent.
In 1840 Plateau married Mile. Clavareau, daughter of a director of tax-collections. She was always a devoted wife and true helpmate to him. Outliving him, she was able to comfort, sustain, and help him when darkness settled over his life. In 1841 his son Félix, now Professor of Zoölogy and Comparative Anatomy in the University of Ghent, was born. During the same year the disease which ended in total blindness made itself felt. For two years he submitted to the most painful treatment in hopes of saving his eye-sight. The trouble which had attacked the right eye extended to the left. During these long months neither his terrible affliction nor his excruciating suffering ever drew a word of complaint from his lips.
The courage which showed itself in this heroic endurance was far from being merely passive. Nothing daunted by what, in a lesser man, would have ended his life's work, Plateau never lost courage. The future must have looked very dark even to his courageous spirit, but he gave no token of failure. Happily, all material anxieties were removed by the action of his countrymen. He was appointed "professeur ordinaire," and a little later a royal order, countersigned by M. Rogier, assured him of the enjoyment of the entire salary and emoluments of his position. A noble recognition of the man and of his services—a recognition fully justified by forty years of fruitful work, and by a series of discoveries "which have made Belgian science illustrious throughout the entire world."
​As soon as Plateau found himself fairly out of the physicians' hands, with restored health, he resumed his experiments with ardor. He was most happy in finding co-laborers who gave him the most efficient and willing help. "Thanks to their generous co-operation," said he, "the career of scientific work remains open to me. I can, in spite of the infirmity with which I have been visited, put in order the materials which I have amassed, and even undertake new researches."
When this experimental work began again, Plateau showed at once that the clouding of his physical sight had only served to clarify his mental vision. At first he could not give up his independence, and for some time he wrote between metallic slips; his assistants soon learned to decipher the writing. Later, however, he gave up this habit, and contented himself with writing to dictation.
His temper was usually calm and equable; he never uttered a complaint on account of the many deprivations which his blindness imposed. He was bright and amusing in his conversation, and yet he was, as all thinkers are, in the main, sober.
His memory, which was naturally a good one, had become phenomenal by cultivation. It was only necessary to hear an ordinary poem read once or twice for him to be able to repeat it accurately. This gift was one of his greatest compensations for the loss of sight, and of incalculable benefit in his experiments made by the hands of others. His method, given by his son-in-law and biographer, G. van der Mensbrugghe, is as follows: In a day devoted to experiment, speaking of the latter years of the physicist's life, he says: "The old man's face is animated; he announces with admirable precision all the precautions to be taken that the apparatus should work. According to his often expressed desire, the assistant acquaints him successively with his operations, even to the smallest point. No manœuvre is left to his personal valuation. The apparatus is at last ready to be set in motion. The master, who imagines and regulates all the dispositions, makes still other suggestions; he assures himself by different means that all is ready in accordance with his will. At last the assistant is asked to operate—the experiment succeeds! What a satisfaction, what a relief for the noble worker who has conceived it! For greater assurance he causes it to be repeated, with various modifications suggested by the descriptions of the observed effects. If all passes as he has foreseen, he at once asks his secretary to write to his dictation all the details of the experiment. No point is forgotten, for the provisional wording ought to represent, as exactly as possible, all that had been verified. But if the observation did not meet his expectations, in spite of the precautions he had deemed necessary, the physicist promised ​himself to think it over again. He would then devote a part of the night to revolving the question again and again under all its aspects, to seek the cause of the failure and the means of future success."
His enthusiasm would sometimes put his assistants' patience to a rather severe test, and he would cry out, "Oh, if I could only see!" but as soon as success crowned his efforts, the indefatigable experimenter loved to express his gratitude. He cross-questioned Nature with more severity because he could only receive her answers by the voice of an interpreter. The thousand obstacles that presented themselves because of his infirmity only suggested a thousand precautions in order to surmount them. His inner vision was so preternaturally clear that he often corrected the observations of his assistants, and taught their eyes to see aright.
The love of scientific accuracy is not so much a mental as a moral quality. Plateau was possessed of a supreme love for truth, which not only made him accurate in his investigations and in the records of his experiments, but it made him careful not to judge others without a full knowledge of the facts. Always ready to ascribe scientific discovery to the right persons, he spared no pains to know who was the true discoverer.
The instructions which he gave to his pupils bore his own peculiar stamp. He used simple language and almost a conversational tone. His phrases were short, incisive, and clear, a fitting medium for the expressions of a mind so unclouded, so direct, and so concentrated. His talents as an experimenter were even more marked than as a speaker—more marked, because it is a far more uncommon gift.
He was an old-fashioned believer. The more deeply he "penetrated into the secrets of Nature, the more he inclined toward the mysteries of the supernatural order," says his biographer.
The picture of his home-life—his delight in and tenderness for his children in his early manhood, and the same gentle benevolence shown toward his grandchildren in his old age—is very beautiful.
As a scientist he is held in very high esteem by the greatest of his contemporaries. Honors were showered upon him by the great scientific societies of Europe. Such men as Arago and Faraday were glad to do him honor.
His earlier work was confined to the subject of the persistence of luminous impressions upon the eye and the determination of several simultaneous impressions under various conditions of motion. Many of the scientific toys of to-day are the outcome of facts and laws established by him, though he is not often accredited with these earlier discoveries. With the study of persistence of visual impression is so closely associated subjective color that ​this soon came under consideration, both accidental color which follows an impression and that caused by juxtaposition. He simplified the subject greatly by making this division of the subject, the first class including all appearances which succeed the contemplation of a bright-colored object, the second those which accompany such contemplation. The phenomena had been observed before, but Plateau was the first who reduced them to law.
Some valuable experiments and formulated theories on the subject of irradiation were begun, but was interrupted by his oncoming blindness.
Before this time, Plateau's attention had been fixed by the spherical form which a drop of oil assumed when introduced into an alcoholic liquid having the same specific gravity as the oil. From this small beginning he developed a most wonderful series of experiments and laws under the title "Memoirs upon the Phenomena which a Free Mass of Liquid presents when removed from the Action of Gravity." Eleven papers upon this general subject appeared between the years 1843 and 1868 in the memoirs of the Academy of Brussels. These included his experiments upon films and the formulation of the laws which govern their union—one of Plateau's most valuable contributions to physical science. He also made some very interesting investigations upon liquid jets, with a number of shorter papers and notes upon various subjects. Most of these papers appeared in the memoirs or bulletins of the Academy of Brussels, a few in the French and German annals of science, "Comptes Rendu de l'Académie des Sciences de Paris," and Poggendorff 's "Annalen." He died September 15, 1883.
It is impossible to read of Plateau's work, carried on for so many years in spite of frail health and total blindness, and not draw a parallel between Huber and himself each of them a man who was the peer of any worker in his own field, though so cruelly handicapped. They are two of the purest, noblest, most pathetic, most heroic figures who adorn the annals of science.