She was staring at him when his visual exploration was over.
Here you find articles in the encylopedia on topics related to the visual arts.
The simplest type of ocellus is exemplified by the exumbral ocellus of Aurelia, a simple patch of pigment-cells interspersed with visual cells, the whole on a level with the remaining ectodermal epithelium.
The eye-pieces or oculars through which, in case of visual observations, the primary images formed by the objective are viewed, are of quite secondary importance as regards definition in the central portion of the field of view.
To the interposition of air is due the fact that all visual images are to some extent blurred.
He extended his hand, introducing himself and swinging into a cheery speech about the visual pleasures of wintertime in Ouray.
The details of the calculation are given in the article Electric conduction, § where also will be found an account of the methods which have been used to measure the velocities of many ions by direct visual observation.
They consist of a varying number of ommatidia or visual elements, covered by a transparent region of the external cuticle forming the cornea.
The brief visual contact was like a caress, warming her cheeks and heart.
The eye end of the telescope tube is removed - a counterpoise to the object end being substituted in its place - and a prism is inserted at the intersection of the visual axis with the transit axis, so that the rays from the object-glass may be reflected through one of the tubes of the transit axis to an eye-piece in the pivot of this tube.
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.
The word is still sometimes employed in this sense, as of the ship's telegraph, by means of which orders are mechanically transmitted from the navigating bridge to the engine room, but when used without qualification it usually denotes telegraphic apparatus worked by electricity, whether the signals that express the words of the message are visual, auditory or written.
Beyond this simple condition the visual organs of the Hydromedusae do not advance, and are far from reaching the wonderful development of the eyes of Scyphomedusae (Charybdaea).
Lindstrom, G., " Researches on the Visual Organs of the Trilobites," K.
CRYSTAL - GAZING, or Scrying, the term commonly applied to the induction of visual hallucinations by concentrating the gaze on any clear deep, such as a crystal or a ball of polished rock crystal.
We might expect persons who have experienced spontaneous visual hallucinations, of the kind vulgarly styled "ghosts" or "wraiths," to succeed in inducing pictures in a glass ball.
As regards scepticism concerning the faculty we may quote what Mr Galton says about the faculty of visualization: "Scientific men as a class have feeble power of visual reproduction..
In these works he attacked the existing theories of externality which to the unphilosophical mind is proved by visual evidence.
The conditions which tend to induce them contain generally, as one element, constrained visual attention prolonged beyond ordinary duration.
These images are created or produced not by an external stimulus, such as is necessary for a visual image (even the after-image is due to the continued excitement of the same organ), but by a mental act of reproduction.
And the visual object-glass of to in.
The most rapid visual binary (leaving aside Capella for the moment) is Equulei, which completes a revolution in 5.7 years.
In importance next to visual observation, and in the opinion of some, surpassing it, is the photographic method.
It will be seen, then, that the visual and photographic foci are now merged in one, and the image is practically as achromatic as that yielded by a reflector.
The largest refracting telescope yet made, viz., that constructed by Gautier for the Paris exhibition of 1900, was arranged on this plan (type F), the stars' rays being reflected along the horizontal axis re rac or of a telescope provided with visual and with photo graphic object-glasses of 49-in.
2 Holtzmann has characterized this as "the right visual angle" for the judgment of the book.
Romas had felt no need to explain his insistence of her wearing it, but Evelyn had explained it acted as a visual identifying piece and also happened to open all the doors on the ship.
In this case the pigment-cells are endodermal, forming a cup of pigment in which the visual cones are embedded.
He maintained that visual consciousness is merely a system of arbitrary signs which symbolize for us certain actual or possible tactual experience - in other words a purely conventional language.
The contents of the visual and the tactual consciousness have no element in common.
The visible and visual signs are definitely connected with tactual experiences, and the association between them, which has grown up in our minds through custom or habit, rests upon, or is guaranteed by, the constant conjunction of the two by the will of the Universal Mind.
It was evident that a similar analysis might have been applied to tactual consciousness which does not give externality in its deepest significance any more than the visual; but with deliberate purpose Berkeley at first drew out only one side of his argument.
The distinction, therefore, between the movement of the eyeballs, elicited from the occipital (visual) cortex, and that of the hand, elicited from the cortex in the region of the central sulcus (somaesthetic), is not a difference between motor and sensory, for both are sensori-motor in the nature of their reactions; the difference is only a difference between the kind of sense and sense-organ in the two cases, the muscular apparatus in each case being an appanage of the sensual.
The only way in which the secondary spectrum can be reduced still further is by the employment of three lenses of three different sorts of glass, by which arrangement the secondary spectrum has been reduced in the case of the Cooke photo visual objective to about I/loth part of the usual amount, if the whole region of the visible spectrum is taken into account.
The other telescope is corrected for visual rays and its image is formed on the plane of the spider-lines of a filar micrometer.
Capella, whose period is only 104 days, was discovered to be double by means of the spectroscope, but has since been measured frequently as a visual binary at Greenwich.
The relation applies not only to the visual but to the spectroscopic binaries; these, having shorter periods than the visual binaries, have generally quite small eccentricities.
A continuous gradation can be traced from the most widely separated visual binaries, whose periods are many thousand years, to spectroscopic binaries, Algol and # Lyrae variables, whose periods are a few hours and whose components may even be in contact, and from these to dumb-bell shaped stars and finally to ordinary single stars.
By means of the spectroscope it is possible to determine the relative orbital velocity of the two components, and this when compared with the period fixes the absolute dimensions of the orbit; the apparent dimensions of the orbit being known from visual observations the distance can then be found.
The method is of very limited application, for in general the orbital velocity of a visual binary is far too small to be found in this way; one of its first applications has been made to a Centauri, with the result that the parallax found in the ordinary way is completely confirmed.
Soc., 1878), the most suitable for visual instruments (" optical achromatism ").
In Hydromedusae, of Schafer.) two kinds of elements: (After (I) visual cells, sensory ectodermal cells, which may develop terminal visual cones; (2) pigment-cells, usually ectodermal, but in one known instance endodermal.
That the mouth at the extremity of the hypo c, Visual cone; n, stome represents the persistent blastopore of nucleus; n.
In the second case, the technique of reading without vocalizing allowed for faster reading and a new, visual way to process verbal information—again, a net gain.
- Visual observation is limited to the range of frequencies to which our eyes are sensitive.
When, for instance, the axons of the ganglion cells of the retina are severed by section of the optic nerve, and thus their influence upon the nerve cells of the visual cerebral centres is set aside, the nerve cells of those centres undergo secondary atrophy (Gadden's atrophy).
The ultra-violet and the visual portion are recorded photographically; Rowland's classical work shows some 5700 lines in the former, and 14,200 in the latter, on a graduated scale of intensities from moo to o, or 0000, for the faintest lines; between a quarter and a third of these lines have been identified, fully 2000 belonging to iron, and several hundred to water vapour and other atmospheric absorption.
The subumbral ocellus of Aurelia is found to be of the inverted type, with the visual cones turned away from the light, as in Tiaropsis amongst Hydromedusae, and here also the pigment is furnished by the endoderm, forming a cup into which the ectodermal visual cells project (Schewiakoff ['31) In) the Stauromedusae tentaculocysts are either absent altogether, as in - St.
As might be expected, in thickened and highly embossed valves thin spaces occur over the visual organ.