See also:

• CAMERA (a Latin adaptation of Gr. Kagapa, an arched chamber)

CAMERA LUCIDA  , an See also:

• OPTICAL

optical See also:

• INSTRUMENT (Lat. instrumentum, from insincere, to build up, furnish, arrange, prepare)

instrument invented by Dr See also:

• WILLIAM
• WILLIAM (1143-1214)
• WILLIAM (1227-1256)
• WILLIAM (1J33-1584)
• WILLIAM (A.S. Wilhelm, O. Norse Vilhidlmr; O. H. Ger. Willahelm, Willahalm, M. H. Ger. Willehelm, Willehalm, Mod.Ger. Wilhelm; Du. Willem; O. Fr. Villalme, Mod. Fr. Guillaume; from " will," Goth. vilja, and " helm," Goth. hilms, Old Norse hidlmr, meaning
• WILLIAM (c. 1130-C. 1190)
• WILLIAM, 13TH

William See also:

• HYDE
• HYDE, THOMAS (1636-1703)

Hyde See also:

• WOLLASTON, WILLIAM (1659--1724)
• WOLLASTON, WILLIAM HYDE (1766-1828)

Wollaston for See also:

• DRAWING

drawing in See also:

• PERSPECTIVE (Lat. peespicere, to see through)

perspective . Closing one See also:

• EYE
• EYE (O. Eng. edge, Ger. Auge; derived from an Indo-European root also seen in Lat. oc-ulus, the organ of vision (q.v.)

eye and looking vertically downwards with the other through a slip of See also:

• PLAIN (O. Fr. plain, from Lat. plenum)

plain See also:

• GLASS
• GLASS (O.E. glees, cf. Ger. Glas, perhaps derived from an old Teutonic root gla-, a variant of glo-, having the general sense of shining, cf. " glare," " glow ")
• GLASS, STAINED

glass, e.g. a See also:

• MICROSCOPE (Gr. µucp6s, small, asenreiv, to %view)

microscope See also:

• COVER (from the Fr. convert, from couvrir, to cover, Lat. cooperire)

cover-glass, held See also:

• CLOSE
• CLOSE (from Lat. clausum, shut)
• CLOSE, MAXWELL HENRY (1822-1903)

close to the eye and inclined at an See also:

• ANGLE (from the Lat. angulus, a corner, a diminutive, of which the primitive form, angus, does not occur in Latin; cognate are the Lat. angere, to compress into a bend or to strangle, and the Gr. ayKOS, a bend; both connected with the Aryan root ank-, to

angle of 450 to the See also:

• HORIZON (Gr. 6pfTwv, dividing)

horizon, one can see the images of See also:

• OBJECTS

objects in front, formed by reflection from thesurface of the glass, and at the same See also:

• TIME (0. Eng. Lima, cf. Icel. timi, Swed. timme, hour, Dan. time; from the root also seen in " tide," properly the time of between the flow and ebb of the sea, cf. O. Eng. getidan, to happen, " even-tide," &c.; it is not directly related to Lat. tempus)
• TIME, MEASUREMENT OF
• TIME, STANDARD

time one can also see through the transparent glass . The virtual images of the objects appear projected on the See also:

• SURFACE

surface of a See also:

• SHEET

sheet of See also:

• PAPER
• PAPER (Fr. papier, from Lat. papyrus)

paper placed beneath the slip of glass, and their outline can be accurately traced with a See also:

• PENCIL (Lat. penicillus, brush, literally little tail)

pencil . This is the simplest See also:

• FORM (Lat. forma)

form of the See also:

• CAMERA (a Latin adaptation of Gr. Kagapa, an arched chamber)

camera lucida . The See also:

• IMAGE (Lat. imago, perhaps from the same root as imitari, copy, imitate)

image (see fig . 1) is, however, inverted and Eye perverted, and it is not very See also:

• BRIGHT, JOHN (1811-188g)
• BRIGHT, SIR CHARLES TILSTON

bright owing to the poor reflecting See also:

• POWER [WILLIAM GRATTAN] TYRONE (1797-1841)

power of unsilvered glass . The brightness of the image is sometimes in- creased by silvering the glass; and on removing a small portion of the See also:

• SILVER

silver the observer can See also:

• OBJECT

object see the image with See also:

• PART

part 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 while he See also:

• SEES

sees the paper through the unsilvered See also:

• APERTURE (from Lat. aperire, to open)

aperture c ,< with the remaining part . This form of the in- Image strument is often used in See also:

• CONJUNCTION (from Lat. conjungere, to join together)

conjunction with the FIG . I. microscope, the See also:

• MIRROR (through O. Fr. mirour, mod. miroir, from a sup-posed Late Lat. miratorium, from mirari, to admire)

mirror being attached to the eye-piece and the See also:

• TUBE (Lat. tuba)

tube of the microscope being placed horizontally . About the beginning of the 19th See also:

• CENTURY (from Lat. centuria, a division of a hundred men)

century Dr Wollaston in-vented a See also:

• SIMPLE

simple form of the camera lucida which gives bright and erect images . A four-sided See also:

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

prism of glass is constructed having one angle of 90°, the opposite angle of 135°, and the two remaining angles each of 67z° . This is represented in See also:

• CROSS

cross-See also:

• SECTION
• SECTION (Lat. sectio, cutting, secare, to cut)

section and in position in fig .

2 . When the pupil of the eye is held See also:

• HALF

half over the edge of the prism a, one sees the image of the object with one half of the pupil and the paper with the other half . The image is formed by successive See also:

• TOTAL

total reflection at the surfaces b c and a b . In the first See also:

• PLACE (through Fr. from Lat. platea, street; Gr. IrAar6s, wide)

place an inverted image (first image) is formed in the See also:

• FACE (from Lat. fades, derived either from facere, to make, or from a root fa-, meaning " appear "; cf. Gr. cbatvstv)

face b c, and then an image of this image is formed in a b, and it is the e, 2nd Image outline of this second image seen See also:

• PRO

pro- jected on the paper that is traced by the FIG . 2 . pencil . It is desirable for two reasons that the image should See also:

• LIE, JONAS LAURITZ EDEMIL (1833—1908)
• LIE, MARIUS SOPHUS (1842–1899)

lie in the See also:

• PLANE

plane of the paper, and this can be secured by placing a suitable See also:

• LENS
• LENS (from Lat. lens, lentil, on account of the similarity of the form of a lens to that of a lentil seed)

lens between the object and the prism . I£ the image does not lie in the plane of the paper, it is impossible to see it and the pencil-point clearly at the same time . Moreover, any slight See also:

• MOVEMENT

movement of the See also:

• HEAD (in 0. Eng. heafad; the word is common to Teutonic languages; cf. Dutch hoofd, Ger. Haupt, generally taken to be in origin connected with Lat. caput, Gr. KerbOvi7)
• HEAD, SIR EDMUND WALKER, BART
• HEAD, SIR FRANCIS BOND, BART

head will cause the image to appear to move relatively to the paper, and will render it difficult to obtain an accurate drawing . Before the application of See also:

• PHOTOGRAPHY (Gr. bias, light, and ypa w, to write)
• PHOTOGRAPHY, CELESTIAL

photography, the camera lucida was of considerable importance to draughtsmen . The advantages claimed for it were its cheapness, smallness and portability; that there was no appreciable distortion, and that its See also:

• FIELD (a word common to many West German languages, cf. Ger. Feld, Dutch veld, possibly cognate with O.E. f olde, the earth, and ultimately with root of the Gr. irAaror, broad)
• FIELD, CYRUS WEST (1819-1892)
• FIELD, DAVID DUDLEY (18o5-1894)
• FIELD, EUGENE (1850-1895)
• FIELD, FREDERICK (18o1—1885)
• FIELD, HENRY MARTYN (1822-1907)
• FIELD, JOHN (1782—1837)
• FIELD, MARSHALL (183 1906)
• FIELD, NATHAN (1587—1633)
• FIELD, STEPHEN JOHNSON (1816-1899)
• FIELD, WILLIAM VENTRIS FIELD, BARON (1813-1907)

field was much larger than that of the camera obscura . It was used largely for copying, for reducing or for enlarging existing drawings .

It will readily be understood, for example, that a copy will be half-See also:

• SIZE

size if the distance of the object from the instrument is See also:

• DOUBLE
• DOUBLE (from the Mid. Eng. duble, the form which gives the present pronunciation, through the Old Er. duble, from Lat. duplus, twice as much)

double the distance of the instrument from the copy . (C . J .