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.
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.
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.
R, Optical section of leptoid (sieve-tube segment) of Phanerogam, with two proteid (companion) cells.
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.
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.
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.
S, Optical section of part of thick-walled stereid of Phanerogam, with almost obliterated cavity and narrow slit-like oblique pits.
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.
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.
The actual finiteness of A imposes a limit upon the separating or resolving power of an optical instrument.
22) are attached to the plate L, their optical axes being normal to the stage T.
L, Optical section of cell of parenchyma in the same moss.
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.
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.
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.
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.
Other physical properties of these solutions, such as density, colour, optical rotatory power, &c., like the conductivities, are additive, i.e.
We may conveniently commence with them on account of their simplicity and great importance in respect to the theory of optical instruments.
The contraction of the diffraction pattern with increase of aperture is of fundamental importance in connexion with the resolving power of optical instruments.
To optical ones can be performed with somewhat shorter waves.
0, Optical section of two adjacent leptoids (sieve-tube segments) of Pteridophyte, with sieve plates (s.
With Reichenbach and Utzschneider, Fraunhofer established in 1809 an optical institute at Benedictbeuern, near Munich, of which he in 1818 became sole manager.