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The Constitution Of Nature
We cannot think of space as finite, for wherever in imagination we erect a boundary, we are compelled to think of space as existing beyond it. Thus by the incessant dissolution of limits we arrive at a more or less adequate idea of the infinity of space.
Radiation - Visible And Invisible
Between the mind of man and the outer world are interposed the nerves of the human body, which translate, or enable the mind to translate, the impressions of that world into facts of consciousness and thought.
Origin And Character Of Radiation
When we see a platinum wire raised gradually to a white heat, and emitting in succession all the colors of the spectrum, we are simply conscious of a series of changes in the condition of our own eyes.
The Atomic Theory In Reference To The Ether
The word atoms has been more than once employed in this discourse. Chemists have taught us that all matter is reducible to certain elementary forms to which they give this name.
Absorption Of Radiant Heat By Gases
We have now to submit these considerations to the only test by which they can be tried, namely, that of experiment.
Formation Of Invisible Foci
This extraordinary deportment of the elementary gases naturally directed attention to elementary bodies in other states of aggregation. Some of Melloni's results now attained a new significance.
Visible And Invisible Rays Of The Electric Light
We have next to examine what proportion the non-luminous rays of the electric light bear to the luminous ones. This the opaque solution of iodine enables us to do with an extremely close approximation to the truth.
Combustion By Invisible Rays
The sun's invisible rays far transcend the visible ones in heating power, so that if the alleged performances of Archimedes during the siege of Syracuse had any foundation in fact, the dark solar rays would have been the philosopher's chief agents of combustion.
Transmutation Of Rays - Calorescence
Eminent experimenters were long occupied in demonstrating the substantial identity of light and radiant heat, and we have now the means of offering a new and striking proof of this identity.
Deadness Of The Optic Nerve To the Calorific Rays
The layer of iodine used in the foregoing experiments intercepted the rays of the noonday sun. No trace of light from the electric lamp was visible in the darkest room, even when a white screen was placed at the focus of the mirror employed to concentrate the light.
Persistence Of Rays
At an early part of this lecture it was affirmed that when a platinum wire was gradually raised to a state of high incandescence, new rays were constantly added, while the intensity of the old ones was increased.
Absorption Of Radiant Heat By Vapors And Odors
We commenced the demonstrations brought forward in this lecture by experiments on permanent gases, and we have now to turn our attention to the vapors of volatile liquids.
Aqueous Vapor In Relation To The Terrestrial Temperatures
We are now fully prepared for a result which, without such preparation, might appear incredible. Water is, to some extent, a volatile body, and our atmosphere, resting as it does upon the surface of the ocean, receives from it a continual supply of aqueous vapor.
Reciprocity Of Radiation And Absorption
Throughout the reflections which have hitherto occupied us, the image before, the mind has been that of a radiant source sending forth calorific waves, which, on passing among the molecules of a gas or vapor, were intercepted by those molecules in various degrees.
Influence Of Vibrating Period And Molecular Form
In the foregoing experiments with gases and vapors we have employed throughout invisible rays, and found some of these bodies so impervious to radiant heat, that in lengths of a few feet they intercept every ray as effectually as a layer of pitch.
Summary And Conclusion Of Radiation
Let us now cast a momentary glance over the ground-that we have left behind. The general nature of light and heat was first briefly described: the compounding of mat-ter from elementary atoms, and the influence of the act of combination on radiation and absorption, were considered and experimentally illustrated.
On Radiant Heat In Relation To The Color And Chemical Constitution Of Bodies
ONE of the most important functions of physical science, considered as a discipline of the mind, is to enable us by means of the sensible processes of Nature to apprehend the insensible.
New Chemical Reactions Produced By Light
MEASURED by their power, not to excite vision, but to produce heat—in other words, measured by their absolute energy—the ultra-red waves of the sun and of the electric light, as shown in the preceding articles, far transcend the visible.
Physical Considerations Of Decomposition Of Light
I sought to determine the particular portion of the light which produced the foregoing effects. When, previous to entering the experimental tube, the beam was caused to pass through a red glass, the effect was greatly weakened, but not extinguished.
Production Of Sky Blue By Decomposition Of Nitrite Of Amyl
When the quantity of nitrite vapor is considerable, and the light intense, the chemical action is exceedingly rapid, the particles precipitated being so large as to whiten the luminous beam. Not so, however, when a well-mixed and highly attenuated vapor fills the experimental tube.
On The Blue Color Of The Sky, And The Polarization Of Skylight
After the communication to the Royal Society of the foregoing brief account of a new Series of Chemical Reactions produced by Light, the experiments upon this subject were continued, the number of substances thus acted on being considerably increased.
The Sky Of The Alps
The vision of an object always implies a differential action on the retina of the observer. The object is distinguished from surrounding space by its excess or defect of light in relation to that space.
The Sky
In the house of Science are many mansions, occupied by tenants of diverse kinds. Some of them execute with painstaking fidelity the useful work of observation, recording from day to day the aspects of Nature or the indications of instruments devised to reveal her ways.
Voyage To Algeria To Observe The Eclipse
THE opening of the Eclipse Expedition was not propitious. Portsmouth, on Monday, December 5, 1870, was swathed by fog, which was intensified by smoke, and traversed by a drizzle of fine rain.
IT is one of the disadvantages of reading books about natural scenery that they fill the mind with pictures, often exaggerated, often distorted, often blurred, and, even when well drawn, injurious to the freshness of first impressions. Such has been the fate of most of us with regard to the Falls of Niagara.
The Parallel Roads Of Glen Roy
THE first published allusion to the Parallel Roads of Glen Roy occurs in the appendix to the third volume of Pennant's Tour in Scotland, a work published in 1776.
Alpine Sculpture
TO account for the conformation of the Alps, two hypotheses have been advanced, which may be respectively named the hypothesis of fracture and the hypothesis of erosion.
Recent Experiments On Fog Signals
THE care of its sailors is one of the first duties of a maritime people, and one of the sailor's greatest dangers is his proximity to the coast at night. Hence the idea of warning him of such proximity by beacon-fires placed sometimes on natural eminences and sometimes on towers built expressly for the purpose.
On The Study Of Physics
I HOLD in my hand an uncorrected proof of the syllabus of this course of lectures, and the title of the present lecture is there stated to be - On the Importance of the Study of Physics as a Means of Education.
On Crystalline And Slaty Cleavage
WHEN the student of physical science has to investigate the character of any natural force, his first care must be to purify it from the mixture of other forces, and thus study its simple action.
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