Inventors

"Conversely, upon the body there falls through the openings 2 and 1 a pencil of rays having the wave length \lambda, polarized in the plane a; of this, the body absorbs a part while it reflects or transmits the remainder; let the ratio of the intensity of the absorbed rays to the incident rays be A and let this be called the absorptive power of the body... The quantities E and A depend upon the nature of the condition of the body.., also upon the form and position of the openings.., the wave length \lambda and the direction of the plane a."

"[I]t will be assumed that perfectly diathermanous bodies are conceivable, that is, such which will absorb none of the incident heat rays of whatever nature these may be, and finally, that a perfect mirror is conceivable, i.e., a body which reflects completely all heat rays."

"A perfect mirror, like every diathermanous body, can itself send out no rays; for if it did (confined in an enclosure of like temperature) it would warm this enclosure... and cool itself more and more."

"[R]adiation in empty space will be investigated..⇒ the [associated] black bodies must have a refracted index which differs infinitely little from 1."

"Before a body... imagine two screens, S1 and S2 placed in which are two openings 1 and 2, whose dimensions are infinitely small with respect to their distance apart, and each of which has a center."

"This investigation will be... simplified if we imagine the enclosure... composed... of bodies which, for infinitely small thickness, completely absorb all rays which fall upon them. I... call such bodies perfectly black, or more briefly, black."

"Through these openings passes a pencil of rays sent out by the body... consider the part [of the pencil], whose lies between \lambda and \lambda + \partial \lambda, and let this be divided into two polarized components, whose planes of polarization are the [perpendicular] planes a and b... passing through the axis of the ray pencil."

"We owe to Kirchhoff..., the first rigorous proof of the celebrated law (...Kirchhoff's law) of the emission and absorption of light and heat, and the application of the same by both Kirchhoff and Bunsen to Spectrum Analysis. The radiation of solids and liquids and gases follows the law exactly when the conditions upon which he founded it are rigorously fulfilled, namely, the complete transformation from one to the other of radiant energy and their intrinsic ."

"A '... must have the same as the medium... then there will be no reflection at its surface, and all incident rays... wholly absorbed."

"Of the heat rays... sent... to a body by its surroundings a part are absorbed, the others are... varied by reflection and . The rays refracted and reflected... pass off... with those sent out by it, without... mutual disturbance..."

"Through the radiations... a body sends out, the quantity of ... it contains will... sustain a loss... equivalent to the ' of those rays, and through the heat rays... it absorbs, a gain... equivalent to the vis viva of the absorbed rays."

"All heat rays follow the same laws in their propagation, which are known for light rays."

"[I]n certain cases an exception to this rule may occur... [when] absorption and the radiation produce other changes in the body.., for example in bodies... chemically changed by light... [etc.]"

"Look here, I have succeeded at last in fetching some gold from the sun."

"Such cases should be excluded on the assumption that neither by means of the rays which it radiates or absorbs, nor by... other influences... does the body... change, if its is kept constant by the addition or the subtraction of heat. Under these conditions... the... heat... transferred to a body in a given time to prevent cooling... in consequence of its radiation, is equivalent to the vis viva of the emitted rays; and the amount of heat... withdrawn... to counterbalance the heating from absorption of radiations, is equivalent to the vis viva of the absorbed rays."

"Heat rays have the same nature as light rays... The invisible heat rays are distinguished from light rays only by the period of or the wave length."

"Let a body which satisfies these conditions be surrounded by an enclosure, having the same temperature [and kept constant], through which no heat rays can penetrate... The body sends out heat rays and is encountered by... heat rays... in part... from the enclosure, in part... thrown back... by reflection from it, absorbing a part of them. Its temperature must thus remain the same, unless heat is withdrawn from it or communicated to it as follows on the principle from which Carnot's law results. For this reason the vis viva of the rays, which it sends out in a certain time, must equal the vis viva of the rays which it absorbs in the same time."

"[M]ost radiations from gases are not exclusively thermal... [T]he substances, cited by Kirchhoff and Bunsen, also give off... chemical.., electrical and fluorescent radiations which Kirchhoff excluded in the proof of his law."

"Fraunhofer discovered that the apparent continuity of a rainbow is an illusion. There are tiny gaps, dim or black arcs of missing colors, too narrow for us to see in the glare of natural rainbows. To say it another way, there are specific colors (specific wavelengths of light) in which sunlight is deficient. Fraunhofer eventually catalogued 576 of these gaps, or "absorption lines": 576 specific wavelengths missing from sunlight. Fraunhofer's career of discovery was cut short by consumption."

"Fraunhofer had busied himself with glass his entire life. Working with glass was his family tradition, and the manufacture of optical lenses and prisms was his life."

"Fraunhofer's secrets of manufacture accompanied him to the grave. His artisanal knowledge was such that, after his death, even the apprentices who worked with him, in the same glass hut and with the same equipment, achieved only limited success in the manufacture of optical glass."

"Fraunhofer made a great many experiments connected with these mysterious lines, anxious to discover, if possible, their meaning, For although he now saw the lines, which had scarcely so much as been seen before, he could not understand them; he could not read what they said. They spoke to him, indeed, about the Sun, but they spoke in a foreign language, the key to which he did not possess."

"By his invention of new and improved methods, machinery, and measuring instruments for grinding and polishing lenses, by his having the superintendence, after 1811, also of the work in glass-melting, enabling him to produce flint and crown glass in larger pieces, free of veins, but especially by his discovery of a method of computing accurately the forms of lenses, he has led practical optics into entirely new paths, and has raised the achromatic telescope to, until then, undreamed of perfection."

"Before we can rightly understand the principles of spectroscopic astronomy, we must go back to the life and work of its founder—Joseph von Fraunhofer. ...Allowing light from the Sun to pass through a prism attached to the telescope, he was amazed to find several dark lines in the spectrum. ...Fraunhofer named the more prominent lines by the letters of the alphabet from A in the red to H in the violet. They are now known as the Fraunhofer lines. ...He expressed the belief that the pair of lines in the solar spectrum which he marked D, coincided with the pair of bright lines emitted by incandescent sodium. Although he doubtless suspected that the lines conveyed intelligence regarding the elements in the Sun, he never was able properly to decipher their meaning. Had he lived he would probably have made the great discovery."

"It will reward enough for me if, by the publication of the present experiment, I have directed the attention of investigators to this subject, which still promises much for physicial optics and appears to open a new field."

"I wished to find out whether a similar bright line could be seen in the spectrum of sunlight as in the spectrum of lamplight, and I found, with the telescope, instead of this, an almost countless number of strong and feeble vertical lines which, however, were darker than the other parts of the spectrum, some appearing to be almost perfectly black."

"In order to receive in the eye all the light diffracted through a narrow opening, and to see the phenomena strongly magnified; still more in order to directly measure the inflection of the light, I placed in front of the objective of a theodolite-telescope a screen in which there was a narrow vertical opening which could be made wider or narrower by means of a screw. By means of a heliostat I threw sunlight into a darkened room through a narrow slit so that it fell upon this screen, through whose opening the light was therefore diffracted. I could then observe through the telescope the phenomena produced by the diffraction, magnified, and yet seen with sufficient brightness; and at the same time I could measure the angles of inflection of the light by means of the theodolite."

"He was the first to observe spectra due to gratings, and with them he made the earliest determination of wave-lengths."

"In all my experiments I could, owing to lack of time, pay attention to only those matters which appeared to have a bearing upon practical optics. I could either not touch other questions, or at most not follow them very far. Since the path thus traced in optical experiments seems to promise to lead to interesting results, it is greatly to be desired that skilled investigators should devote attention to it."

"Up to the present time, in experiments on diffraction there has been no instrument, except a magnifying-glass, which could be used with profit; and this may perhaps be one of the reasons why in this field of physical optics we are so backward, and why we know so little of the laws of this modification of light."

"Fraunhofer's publication of 1814 did not receive prompt recognition, nor did his papers of 1821 and 1823. Physicists were fighting over the emission and wave theories of light. The attention of chemists was concentrated upon Dalton's atomic theory and the Berthollet-Proust controversy over the law of definite proportions. The full explanation of the new fact brought forth by Fraunhofer was not given for nearly forty years. He himself had failed to find the key to the hieroglyphics of the solar lines, the "Fraunhofer lines," nor had he clearly defined the role which the spectral lines were destined to play in chemical analysis."

"The number of different optical phenomena has become in our time so great that caution must be taken so as to avoid being deceived, and also to refer the phenomena to the simple laws."

"Land was legendary for his eccentric and exhausting work habits, which dated back to his Harvard days. Like the proverbial mad scientist, when Land was immersed in a project, he would lock himself in the lab for days on end, stopping only long enough to eat and often not bothering to change clothes. When he was on one of these jags, Land's assistants would be scheduled in shifts to keep up with him since they had a tendency to fold at the knees without sleep."

"Besides energy, the dominant impressions Land created were artistic sensibility, a sense of drama, delight in experiment, relentless optimism. Less evident was a remarkable ability to keep both work and people in compartments. Less than six feet tall, Land had intense eyes and a shock of black hair that riveted attention on him. Despite a soft voice and frequent use of half-sentences, Land was able to convert interior monologues into dramatic public presentations. The watchword was: "If anything is worth doing, it's worth doing to excess.""

"I always thought of myself as a humanities person as a kid, but I liked electronics. Then I read something that one of my heroes, Edwin Land of Polaroid, said about the importance of people who could stand at the intersection of humanities and sciences, and I decided that's what I wanted to do."

"Din never had an ordinary reaction to anything!"

"In my opinion, neither organisms nor organizations evolve slowly and surely into something better, but drift until some small change occurs which has immediate and overwhelming significance. The special role of the human being is not to wait for these favorable accidents but deliberately to introduce the small change that will have great significance. To treat young men like men; to use modern recording techniques to capture the moment of exciting teaching; to gather ninety great men out of our one-hundred and seventy million — these, in retrospect, will seem like small changes indeed if they succeed in building a generation of greatness."

"Since the violet rays through the objective of the theodolite telescope have a shorter focal length than the red rays, it is evident why the eye-piece must be displaced in order to see plainly the lines in the different colors."

"Whether Newton saw the lines or not, he seems to have paid no especial heed to them. In the year 1802, Dr. W. H. Wollaston using, a slit one-twentieth of an inch in width, noted at least four fine dark lines crossing the solar spectrum. Supposing them to be merely 'natural boundaries' of the different colour-bands, he too inquired no further; and there still for a while the matter rested. Nobody yet suspected, even vaguely, what great future results lay enfolded in the casual discovery of these few slight lines. Not many years later the matter was taken up by Fraunhofer, an able German optician."

"Edwin Land worked passionately to realize his vision for the betterment of society. … His vision of science for the public was a great one, and highly original. … Although Edwin Land must have realized that much about him was unique, he tried to identify those elements of his own being and experience that could be replicated to the benefit of his nation and the world. … As Ken Olsen observed in his talk this morning about Land and Polaroid, knowing where you want to go is a big advantage."

"I would urge that just as democracy initially meant the right of man to defend himself, to have a sword, and then meant the right to write, and then meant the right to read — so, now, democracy means the right to have the scientific experience."

"A contemporary man who has not participated intimately in actual work in science is, in my opinion, not a modern man. I believe that this experience in science should come early in the life of all of our pupils."

"The role of science is to be systematic, to be accurate, to be orderly, but it certainly is not to imply that the aggregated, successful hypotheses of the past have the kind of truth that goes into a number system."

"There are areas where untrained people may work effectively and with limited equipment. Our pupil doesn't need a big laboratory to do this, he needs freedom; he needs encouragement."

"I believe there are two opposing theories of history, and you have to make your choice. Either you believe that this kind of individual greatness does exist and can be nurtured and developed, that such great individuals can be part of a cooperative community while they continue to be their happy, flourishing, contributing selves — or else you believe that there is some mystical, cyclical, overriding, predetermined, cultural law — a historic determinism. The great contribution of science is to say that this second theory is nonsense. The great contribution of science is to demonstrate that a person can regard the world as chaos, but can find in himself a method of perceiving, within that chaos, small arrangements of order, that out of himself, and out of the order that previous scientists have generated, he can make things that are exciting and thrilling to make, that are deeply spiritual contributions to himself and to his friends. The scientist comes to the world and says, "I do not understand the divine source, but I know, in a way that I don't understand, that out of chaos I can make order, out of loneliness I can make friendship, out of ugliness I can make beauty." I believe that men are born this way — that all men are born this way. I know that each of the undergraduates with whom I talked shares this belief. Each of these men felt secretly — it was his very special secret and his deepest secret — that he could be great. But not many undergraduates come through our present educational system retaining this hope. Our young people, for the most part — unless they are geniuses — after a very short time in college give up any hope of being individually great. They plan, instead, to be good. They plan to be effective, They plan to do their job. They plan to take their healthy place in the community. We might say that today it takes a genius to come out great, and a great man, a merely great man, cannot survive. It has become our habit, therefore, to think that the age of greatness has passed, that the age of the great man is gone, that this is the day of group research, that this is the day of community progress. Yet the very essence of democracy is the absolute faith that while people must cooperate, the first function of democracy, its peculiar gift, is to develop each individual into everything that he might be. But I submit to you that when in each man the dream of personal greatness dies, democracy loses the real source of its future strength."

"The fact that civilization is becoming more intricate must not mean that we treat men for a longer period as immature. Does it not mean, perhaps, the opposite: that we must skillfully make them mature sooner, that we must find ways of handling the intricacy of our culture?"

"I think we must say this to each department: "Sharpen up the edges of ideas for the students in fields other than your own. They will not have years in which to find out what you meant, years during which they might achieve a sense of rich insight into your domain. But they are intelligent, they are earnest in their own department; they will profit all their lives from one year of brilliant teaching.""

"Now this error in attitude — mistaking these men for boys — permeates the whole scholastic domain, permeates it so thoroughly that it is hard for anyone within the domain to recognize it. What do I mean by saying that a man is treated as a boy? I mean that he is told, the moment he arrives, that his secret dream of greatness is a pipe-dream; that it will be a long time before he makes a significant, personal contribution — if ever. He is told this not with words. He is told this in a much more convincing way. He is shown, in everything that happens to him, that nobody could dream that he could make a significant, personal contribution."

"Most large industrial concerns are limited by policy to special directions of expansion within the well-established field of the company. On the other hand, most small companies do not have the resources or the facilities to support "scientific prospecting." Thus the young man leaving the university with a proposal for a new kind of activity is frequently not able to find a matrix for the development of his ideas in any established industrial organization."

"As I visualize it, the business of the future will be a scientific, social and economic unit. It will be vigorously creative in pure science where its contributions will compare with those of the universities... the machinist will be proud of and informed about the company's scientific advances; the scientist will enjoy the reduction to practice of his basic perceptions. … year by year our national scene would change in the way, I think, all Americans dream of. Each individual will be a member of a group small enough so that he feels a full participant in the purpose and activity of the group. His voice will be heard and his individuality recognized."