The investigation of this question upon the elastic solid theory will depend upon how we suppose the solid to vary from one optical medium to another.
So long as the particles are supposed to be very small and to differ little from their environment in optical properties, there is little difference between the electric and the elastic solid theories, and the results expressing the character of the scattered light are equivalent to (5).
We learn that the light dispersed in the direction of primary vibration is not only of higher order in the difference of optical quality, but is also of order k 2 c 2 in comparison with that dispersed in other directions, where c is the radius of the sphere, and k=21r/X as before.
In the optical examination we may, if we prefer it, polarize the primary light; but it is usually more convenient to analyse the scattered light.
The focal length of the objective and the distance between the optical centre of the lens and the webs are so arranged that images of the divisions are formed in the plane of the webs, and the pitch of the screw is such that one division of the scale corresponds with some whole number of revolutions of the screw.
An originally unanticipated difficulty has arisen from the fact that the reseau-lines have not been ruled on plates of optical glass with optical surfaces, and that, in consequence of irregular refraction in the glass plate, the rays do not always pass through the silver film-lines in a direction strictly normal to the silvered surface; therefore, if the sensitive surface of the photographic plate is not in contact with the silver film of the reseau, the undeveloped photographic copy of the reseau may in such a case not be an exact reproduction of the silvered reseau.
61, p. 444), and the instrument contains many elegant mechanical and optical details due to Horace Darwin and Messrs Zeiss respectively.
The distance between the centres of the two spectrographs shall be equal to the distance between the optical axes of the two viewing microscopes.
22) are attached to the plate L, their optical axes being normal to the stage T.
Malt, tinware, flour and grist-mill products, boilers, stoves and ranges, optical supplies, wall-paper, cereals, canned goods, cutlery, tin cans and wagons are manufactured, and there are also extensive nurseries.
By this time he had ceased to devote himself to pure mathematics, and in company with his friends Mersenne and Mydorge was deeply interested in the theory of the refraction of light, and in the practical work of grinding glasses of the best shape suitable for optical instruments.
His optical investigations are perhaps the subject in which he most contributed to the progress of science; and the lucidity of exposition which marks his Dioptrics stands conspicuous even amid the generally luminous style of his works.
The chief centres for the manufacture of cutlery are Chfittelerault (Vienne), Langres (Haute-Marne) and Thiers (Puy-de-Dme); for that of arms St Etienne, Tulle and Chttelerault; for that of watches and clocks, Besancon (Doubs) and Montbliard (Doubs); for that of optical and mathematical instruments Paris, Morez (Jura) and St Claude (Jura); for that of locksmiths ware the region of Vimeu (Pas-de-Calais).
The mistake, shown in all the old maps of Australia, had originated in a curious optical illusion.
Geometrical optics, physical optics, meteorological optics, &c. Greek terminology included two adjectival forms - ra 01rTixfi, for all optical phenomena, including vision and the nature of light, and I) &rTLiO (sc. OEcopfa), for the objective study of light, i.e.
Etymologically the word implies that the messages are written, but its earliest use was of appliances that depended on visual signals, such as the semaphore or optical telegraph of Claude Chappe.
In length by any mirrors which can be practically constructed would be like attempting optical experiments with mirrors one-hundred-thousandth of an inch in diameter.
The radiations interfere in an optical sense of the word, and in some directions reinforce each other and in other directions neutralize each other, so making the resultant radiation greater in some directions than others.
- Optical Section of a Statocyst of Octorchis.
K, Optical section of two adjacent leptoids of the Moss Polytrichum juniperinum.
L, Optical section of cell of parenchyma in the same moss.
0, Optical section of two adjacent leptoids (sieve-tube segments) of Pteridophyte, with sieve plates (s.
R, Optical section of leptoid (sieve-tube segment) of Phanerogam, with two proteid (companion) cells.
S, Optical section of part of thick-walled stereid of Phanerogam, with almost obliterated cavity and narrow slit-like oblique pits.
This is the principle of the kaleidoscope, an optical toy which received its present form at the hands of Sir David Brewster about the year 1815, and which at once became exceedingly popular owing to the beauty and variety of the images and the sudden and unexpected changes from one graceful form to another.
There is a considerable export of quartz crystal, commercially known as "Brazilian pebbles," used in optical work.
He now employed himself in making optical glasses, and in engraving on metal, devoting his spare time to the perusal of works on mathematics and optics.
With Reichenbach and Utzschneider, Fraunhofer established in 1809 an optical institute at Benedictbeuern, near Munich, of which he in 1818 became sole manager.
B, The diblastula has become a trochosphere by the development of the ciliated ring y r (optical section).
D, Further advanced trochosphere (optical section).
His optical investigations led him to adopt in an imperfect form the undulatory theory of light, to anticipate the doctrine of interference, and to observe, independently of though subsequently to F.
His researches extended to almost every branch of physical science, but his most important work was of an optical character.
The proof of this statement rests on the fact that if the hydrogen atoms were not co-planar, then substitution derivatives (the substituting groups not containing asymmetric carbon atoms) should exist in enantiomorphic forms, differing in crystal form and in their action on polarized light; such optical antipodes have, however, not yet been separated.
If, however, two compounds only differ with regard to the spatial arrangement of the atoms, the physical properties may be (I) for the most part identical, differences, however, being apparent with regard to the action of the molecules on polarized light, as is the case when the configuration is due to the presence of an asymmetric atom (optical isomerism); or (2) both chemical and physical properties may be different when the configuration is determined by the disposition of the atoms or groups attached to a pair of doubly-linked atoms, or to two members of a ring system (geometrical isomerism or allo-isomerism).
Kauffmann (Ber., 1906, 39, p. 1 959) attempted an evaluation of the effects of auxochromic groups by means of the magnetic optical constants.
The larger ones polarize light, have angular outlines like those of crystals, and may even show twinning and definite optical properties by which they can be identified as belonging to felspar, augite or some other rock-forming mineral.
Other physical properties of these solutions, such as density, colour, optical rotatory power, &c., like the conductivities, are additive, i.e.
The d modification is of the commonest occurrence, the other forms being only known as synthetic products; for this reason it is usually termed glucose, simply; alternative names are dextrose, grape sugar and diabetic sugar, in allusion to its right-handed optical rotation, its occurrence in large quantity in grapes, and in the urine of diabetic patients respectively.
In their optical characters the micas exhibit considerable variations.
Dark coloured micas are strongly pleochroic. Accurate determinations of the optical orientation, as well as the symmetry of the etching figures on the cleavage planes, seem to suggest that the micas, except muscovite, may be anorthic rather than monoclinic in crystallization.
Sheets of mica are used as a surface for painting, especially in India; for lantern slides; for carrying photographic films; as a protective covering for pictures and historical documents; for mounting soft and collapsible natural history specimens preserved in spirit; for the vanes of anemometers; mirrors of delicate physical instruments; for various optical and many other purposes.
Thus in 1857 he went to Peru in order to determine the magnetic equator; in1861-1862and 1864, he studied telluric absorption in the solar spectrum in Italy and Switzerland; in 1867 he carried out optical and magnetic experiments at the Azores; he successfully observed both transits of Venus, that of 1874 in Japan, that of 1882 at Oran in Algeria; and he took part in a long series of solar eclipse-expeditions, e.g.
We may conveniently commence with them on account of their simplicity and great importance in respect to the theory of optical instruments.
This expression for the intensity becomes rigorously applicable when f is indefinitely great, so that ordinary optical aberration disappears.
The contraction of the diffraction pattern with increase of aperture is of fundamental importance in connexion with the resolving power of optical instruments.
The actual finiteness of A imposes a limit upon the separating or resolving power of an optical instrument.
4, AB represents the axis of an optical instrument (telescope or microscope), A being a point of the object and B a point of the image.
In virtue of the general law that the reduced optical path is stationary in value, this retardation may be calculated without allowance for the different paths pursued on the farther side of L, L', so that the value is simply PL - PL'.
Our investigations and estimates of resolving power have thus far proceeded upon the supposition that there are no optical imperfections, whether of the nature of,, a regular aberration or dependent upon irregularities of material and workmanship. In practice there will always be a certain aberration or error of phase, which we may also regard as the deviation of the actual wavesurface from its intended position.