Online Encyclopedia

Search over 40,000 articles from the original, classic Encyclopedia Britannica, 11th Edition.

SPECIFICATION (from Med. Lat. specifi...

Online Encyclopedia

Originally appearing in Volume V25, Page 617 of the 1911 Encyclopedia Britannica.

» Make a correction to this article.
» Add information or comments to this article.

Encyclopedia Home :: SOU-STE

Spread the word:

del.icio.us it!

See also:

SPECIFICATION (from Med. Lat. specificatio, specificare, to enumerate or mention in detail)

SPECIFICATION (from Med. See also:
LAT
Lat. specificatio, specificare, to enumerate or mention in detail) , any detailed statement, especially one on which an estimate or See also:

plan is based, as the specification of a builder or architect (see See also:

BUILDING

BUILDING). In patent See also:

law a specification is a description of an invention. An application for a patent must be accompanied by a specification, either provisional or See also:

COMPLETE

complete. If a complete specification does not accompany the application, it must be forwarded usually within six months of the date of application, otherwise the application is deemed to be abandoned. A provisional specification declares the nature of the invention in See also:

general terms, while a complete specification describes the invention in detail, and shows the manner in which it is to be carried out (see further See also:

PATENTS

PATENTS). In the See also:

CIVIL

civil law (see AccEssroN) specification was the working up of a thing into a new product; for example, the making of See also:

BREAD

bread from See also:

GRAIN (derived through the French from Lat. granum, seed, from an Aryan root meaning " to wear down," which also appears in the common Teutonic word " corn ")

grain. The effect of specification was that the See also:

ORIGINAL

original owner lost his See also:

TITLE (0. Fr. title, mod. titre, from Lat. titulus)

title in favour of the creator of the new product, but had an See also:

ACTION

action for the value of the materials.rigid See also:

STEEL, FLORA ANNIE (1847– )

steel See also:

WIRE (A.S. wir, a wire; cf. Swed. vire, to twist, M.H.G. wiere, a gold ornament, Lat. viriae, armlets, ultimately from the root wi, to twist, bind)

wire or See also:

gold frames, with fastening-pieces over the ears; single or See also:

double See also:

eye-glasses, and See also:

hand-glasses, or lorgnettes, being varieties of See also:

FORM (Lat. forma)

form, according to the circumstances and the wearer's See also:

TASTE (from Lat. taxare, to touch sharply; tangere, to touch)

taste. Preserves.—Preserves are used to conceal deformities or to protect the eyes in the many conditions where they cannot tolerate See also:

bright See also:

LIGHT

light, such as ulceration and inflammation of the cornea, certain diseases of the See also:

IRIS

iris, ciliary See also:

BODY

body, choroid, and retina. They are made of bluish, " smoked," or almost See also:

black coloured See also:

glass, and are of very various shapes, according to the amount of obscuration necessary. Prisms.—Prisms are of See also:

GREAT

great value in cases of double See also:

VISION (from Lat. videre, to see), or SIGHT

vision due to a slight tendency to squinting, caused by weakness or over-action of the See also:

MUSCULAR

muscular apparatus of the eyeball. Prisms deflect rays of light towards their bases.

Hence, if a See also:

PRISM (Gr. rrpivµa, properly a thing sawn, Irpii"ety, to saw)

prism is placed in front of the eye with its See also:

BASE

base towards the See also:

NOSE (O.Eng. nosu, cf. Dutch neus, Swed. nos, snout; the Aix in Provence. Both at Aix and at Lyons he acquired great connexion with O.Eng. nasu is obscure, cf. Ger. Nase, Lat. pares, distinction by his labours during outbreaks of the plague. In nostrils,

nose, a See also:

ray of light falling upon it will be See also:

bent inwards, and seem to come from a point farther out from the See also:

AXIS (Lat. for " axle ")

axis of vision. Conversely, if the base of the prism is turned towards the See also:

temple, the ray of light will seem to come from a point nearer the axis, and will induce the eye to turn inwards, to converge towards its See also:

FELLOW

fellow. In cases of myopia or See also:

SHORT, FRANCIS JOB (1857– )

short-sight owing to weakness of the See also:

INTERNAL

internal recti muscles, the eyes in looking at a near See also:

OBJECT

object, instead of converging, tend to turn outwards, and so double vision results. If a suitable prism is placed in front of the eyes the double vision may be prevented. These prisms may be combined with See also:

CONCAVE

concave lenses, which correct the myopia, or, since a concave See also:

lens may be considered as composed of two prisms See also:

UNITED

united at their apices, the same effect may be obtained by making the distance between the centres of the concave lenses greater than that between the centres of the pupils. Again, to obviate the See also:

NECESSITY (Lat. necessitas)

necessity for excessive convergence of the eyes so See also:

COMMON

common in hypermetropia, the centre of the See also:

PUPIL (Lat. pupillus, orphan, minor, dim. of pupus, boy, allied to puer, from root pm- or peu-, to beget, cf. "pupa," Lat. for " doll," the name given to the stage intervening between the larval and imaginal stages in certain insects)

pupil should be placed outside the centre of the corrective See also:

CONVEX

convex lenses; these will then See also:

ACT (Lat. actus, actum)

act as prisms with their bases inwards. Where, on the other hand, there is no tendency to squinting, care must be taken in selecting See also:

SPECTACLES

spectacles that the distances between the centres of the glasses and the centres of the pupils are quite equal, otherwise squinting, or at any See also:

RATE

rate great fatigue, of the eyes may be induced. Spherical Lenses.—Biconcave, biconvex and concavo-convex (meniscus) lenses are employed in ophthalmic practice in the treatment of errors of See also:

refraction. Until recently these spherical lenses were numbered in terms of their See also:

FOCAL

focal length, the See also:

INCH (O. Eng. ynce from Lat. uncia, a twelfthpart; cf. " ounce," and see As)

inch being used as the unit. Owing principally to See also:

DIFFERENCES, CALCULUS OF (Theory of Finite Differences)

differences in the length of the inch in various countries this method had great inconveniences, and now the unit is the refractive See also:

POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power of a lens whose focal length is one See also:

METRE ((terpuc?, sc. rFxvf, from Gr. Or poi', measure)

metre. This unit is called a " dioptric " (usually written " D"). A lens of twice its strength has a refractive power of 2 D, and a focal length of See also:

HALF

half a metre, and so on.

Concave Lenses are used in the treatment of myopia or short-sight. In this See also:

CONDITION (Lat. condicio, from condicere, to agree upon, arrange; not connected with conditio, from condere, conditum, to put together)

condition the eye is elongated from before back-wards, so that the retina lies behind the See also:

PRINCIPAL

principal See also:

FOCUS (Latin for " hearth " or " fireplace ")

focus. All See also:

OBJECTS

objects, therefore, which See also:

lie beyond a certain point (the conjugate focus of the dioptric See also:

SYSTEM

system of the eye, the far point) are indistinctly seen; rays from them have not the necessary divergence to be focused in the retina, but may obtain it bytheinterposition of suitable concave lenses. Concave lenses should never be used for See also:

WORK

work within the far point; but they may be used in all cases to improve distant vision, and in very short-sighted persons to remove the far point so as to enable See also:

FINE

fine work such as sewing or See also:

READING

reading to be done at a convenient distance. The weakest pair of concave lenses with which one can read clearly test types at a distance of 18 ft. is the measure of the amount of myopia, and this fully correcting glass may be worn in the slighter forms of short-sight. In higher degrees, where full correction might increase the myopia by inducing a See also:

STRAIN (through O. Fr. straindre, estraindre, mod. i treindre, from Lat. stringere, to draw tight, related to stress, stretch, string, &c.)

strain of the See also:

ACCOMMODATION (Lat. accommodare, to make fit, from ad, to, cum, with, and modus, measure)

accommodation, somewhat weaker glasses should be used for near work. In the highest degrees the complete correction may be employed, but lorgnettes are generally preferred, as they can be removed when the eyes become fatigued.

End of Article: SPECIFICATION (from Med. Lat. specificatio, specificare, to enumerate or mention in detail)

Additional information and Comments

There are no comments yet for this article.

» Add information or comments to this article.

Please link directly to this article:
Highlight the code below, right click, and select "copy." Then paste it into your website, email, or other HTML.

Site content, images, and layout Copyright © 2006 - Net Industries, worldwide.
Do not copy, download, transfer, or otherwise replicate the site content in whole or in part.

Links to articles and home page are always encouraged.

[back]
SPECIFIC PERFORMANCE

[next]
SPECTACLES