CAMEO. 



CAMERA LUCIDA. 



Tiltrhr the Sainian ; * though Mote writer* speak of Mnenrchut, the 

 father ot Pythagoras, u MI engraver of signets. There ha* been 

 much discussion respecting the age and genealogy of Theodoras of 

 Sunos, and whether there were one or two wulpton of that mine ; 

 the probability U that there were two. hut the date of the Theodora* 

 referred to by Herodotus U pretty well determined by the circura- 

 itanoe for which the historian mention* him, Polycrates having been 

 murdered in 5M B.C. It u not, however, in the opinion of some, 

 absolutely clear whether Theodorus engraved the (tone or merely 

 chased the metal of the ring of Polycrates. (Muller, ' Archaol. der 

 Kuiwt.,' $ 97.) The first name of very great note that occurs in this 

 branch of art u that of Pyrgoteles, who lived in the time of Alexander 

 the Great, and who alone was permitted to engrave the portrait of 

 Alexander. Tryphon deserves mention also in this place, being the 

 author of a beautiful and well known cameo in the Marlborough col- 

 lection, representing the marriage of Cupid and Psyche. He is sup- 

 posed, on good authority, to hare lived under the immediate successors' 

 of Alexander in Maw 



The age of Augustus is remarkable for the excellence of the gem 

 engravers who were then tiring. Among these Dioscorides, or more 

 correctly Dioscouridos, held the highest rank. He seems, hem 

 hare worked chiefly in intaglio. Some of his productions have reached 

 our times, and prove that the estimation in which he was held waa not 

 undeterred. Dioseoride* was under Augustus what Pyrgoteles had 

 been under Alexander. From Augustus down to Marcus Aurelius 

 there were engravers of gems, both in cameo and intaglio, of very dis- 

 tinguished merit. They were chiefly Grecian artista who settled in 

 Rome. There were, however, some Roman gem-engravers who held a 

 respectable rank, but the list is not considerate . 



The Greek artist* preferred representing the naked figure, and the 

 finest works produced in Greece are seldom draped, while those exe- 

 cuted in Rome, whether by native or by Greek artists, are for the most 

 part clothed. Dioscorides continued to follow the taste of his own 

 nation, and all his figures, with the exception of a Mercury, in the 

 cabinet of France, are believed to be naked. 



It is impossible to describe works of this sort, containing BO mm -h 

 fine detail, with sufficient accuracy to convey a just idea of their 

 merit*. They must be seen and examined with care, to be properly 

 appreciated. Celebrated cameos are preserved in most of the great 

 museums of Europe. One of the most famous works is that known as 

 the Uonsago cameo, which has the heads of Ptolemy II. and Arsinoc I 

 nearly six inches long ; it is now in the possession of the Emperor ol 

 Russia. Another of the finest cameos known is the Apotheosis ol 

 Augustus, in the collection at Vienna. It represents Augustus, his 

 wife Livia, as Rome, accompanied by her family, with Neptune anc 

 Cybele ; another is of an Imperial Eagle ; also a Ptolemy and Antinoe 

 Ac., Ac. In the French collection the sardonyx of Tiberius is one o: 

 the best known : it exhibits the Apotheosis of Augustus and the 

 prince* of the house of Tiberius ; a Jupiter .ttgiochus is a very fine 

 specimen : to which may be added the Apotheosis of Germanicus ; anc 

 one of Agrippina and Oermanicus; with others, particularly some 

 portrait* of great interest. We possess in this country some camei of 

 first-rate excellence, but they are chiefly in private collections. Almos 

 without exception the most famous works of this kind are remarkal.h 

 for the different strata or zones of colour which they exhibit, as well a. 

 for their exquisite design and execution. 



The ancient* were fond of decorating their drinking-cups wit) 

 precious stone* and ramri. They called such vessel* ' gemma; potarifc. 

 Many of them are preserved in the cabinets of the curious. They are 

 usually of sardonyx. 



The workers in cameo not only exercised their skill in the cutting 

 or engraving, but also in so arranging their subject and the composition 

 of it* detail* a* to make the different colours or zones of the stones 

 answer for part* of the design ; as, for example, in relieving fruit 

 flowers, or drapery, in colour, while the other parts, as the flesh of s 

 portrait or figure, were left white ; or cutting the subject entirely ii 

 white, and working no deeper into the stone than the first layer o 

 colour ; thus making, or rather leaving, a natural dark back-groum 

 for the design. These irregularities or accidents, are sometime 

 taken advantage of so skilfully, that it is very difficult to decid 

 whether the variety u the effect of art, or really the natural colour o 

 



The ancients were so partial to this variously-coloured work, tha 

 they imiuu.1 the material, in glass or paste, and exquisite specimens 

 of ancient pastes occur in the museums of this country and th 



le name* of Rome who exercised it will bear comparison with those of 

 [most any age. The greater part of these were Italian*, but two oi 

 most celebrated were natives of Germany, and are jtixlly c -nlitlwl 



particular commemoration. The work* of John Picklcr and 

 Awrence Matter challenge competition with the finest ant 

 <:>ttcr has left a valuable work on hi* art, entitled ' IV 

 intique de graver en Pierree fines,' &c. Raspe's 'Catalog 

 'assie's Gems ' may also be consulted with advantage by those who 

 eeire to extend their knowledge on this subject; as well as tin- 

 works of Millin. ' Introduction h I'fitude dee Pierres grarees;' Kaoul 

 tochette, ' Lettre ft M. Schorn;' Viaconti, ' Iconographie Ore. 

 Impronte Gernniarie dull' Institute;' Muller, 'An!. 

 Kunst/ 818815, *c. 



The practice of working camei on shells, fmirlii/li, .in of oomparatirely 

 modern introduction in Italy ; but it is now carried to so great an 

 ixtent, in Rome partictilarly, and exercised with such success, that we 

 eel fully justified in including it in our notice of the art. The subject 

 s worked in riliero in the white portion or outer crust of the shell, 

 while the inner surface, of a pink or reddish-brown tint, is left for tin 



goad. 



The art has never been sufficiently encouraged in this country to 

 ead any great number of artiste to pursue it exclusively ; but England 

 las, notwithstanding, produced a few eminent gem-engraver*. H 

 names of Marchant, Brown, Tassie, and Pistrucci, particularly deserve 

 lonourable mention. 



CAMERA LUCIDA, an instrument used for drawing, by which th. 

 mages of external objects are thrown upon a plane or curved surface. 

 Camera lucida signifies the light chamber, though the instrument 

 contains no chamber ; but it was so called because of its bearing :\ 

 certain affinity to the camera obscura, a much older instrument, am! 

 after which it was named. [CAMERA OBSCURA.] 



The camera lucida is an invention of the late Dr. Wollaston. 

 depends upon the phenomenon [REFRACTION] that when li^ht i 

 attempted to be thrown into a rarer medium from a denser at 

 than a certain angle, depending upon the two media, none wi) 

 through, but all will be reflected. The following is the description 

 of Dr. Wollaston's apparatus; modifications may be found :i 

 dington's ' Optical Instruments ' and Sir David Brewster's treatise ' On 

 Optics.' We omit detail of fittings and adjustments. 



A B c D is the section of a glass prism, having an angle A D c of 135. 

 This is presented to the object to be represented in such a way that 



K 



At the decline of the Roman empire gem-engraving fell with th 

 other arts, ami it was not till a Ut period that the taste and muni I 

 ceoce of the Florentine family of Medici caused it* revival in Italy, an 

 tempted artist* to devote themselves to it* practice. It was muc 1 

 encouraged in the 15th century. The wealthy required such work 

 for ornamenting their drew, for inlaying and embossing vases, an 

 similar display ; and as object* in nttrr* had a richer effect than others 

 oMneo-ooUacUng became a passion in Italy. Vasari and Marietti ma 

 be referred to as the historians o( tin Italian gem-engraven of tl,. 

 period: and the 15th and 16th cwtaries will be found to boast severs 

 very distinguished artists in this class. In the succeeding century 

 there was a coosiderabfe falling off, but in the 18th the art again rose, an 



the pencils of rays proceeding from it fall on the surface c D at an 

 angle of 45 or nearly so, and therefore by the preceding princip: 

 reflected on A T>, and again from A n to the eye, through an opening K I., 

 which excludes all except the end of the prism at A, and a part i>i tin 

 sheet of paper or other Hut surface fi H. Hence the image of Q i'> 

 thrown towards the visible part of the pajHT, and the eye viewing lioth 

 the image and the sheet of paper (with dilfcivnt parts nf the pupil. 

 however, which creates a difficulty in using this instrument) the 

 observer is enabled to trace the object upon the paper by means of 

 one of the following adjustments : 



1. If Q be very distant, so that the rays of the pencils are i 

 p:u .illcl. those rays will emerge nearly parallel, or the image will be at 

 about the same distance beyond a H in appearance as the object Q i 

 b.-j,.iid B c. But the image must appear to be thrown upon the paper, 

 or it cannot be distinctly traced. Either therefore the image of the 

 paper must be removed to that of the object, or that of the object 

 must be brought up to the pap. r. For long-sighted people, or those 

 who see objects best at a distance, the first is most advantageous. It 

 is done by placing a concave glass M, the principal focus of which shall 

 be in or near the paper. The consequence is, that the pencils from the 

 points of the paper are rendered nearly larallcl, and by an adjustment 

 for raising or lowering the lens the image of o. may be made to appear 

 to coincide with that of tin pip.. But for short-sighted person 

 require near objects or divergent rays, the end may be answered by 

 i inpl'iying. ini-tv.nl of the convex lens at M, a concave lens at J>", which 

 makes the r.i- nage diverge, and by adjustment of which the, 



may be brought to appear a* jioiieils diverging from the paper. Mr. 

 c.KldinRton DM remarked that this lens must produce on unnecessary 

 distortion .if the image, nnd that a short-sighted person had better use 

 the convex lens at M, in the manner of a long-sighted person ; usiui; 

 spectacles, or placing a concave h-ns at K L, to bring the images nearer, 

 or to render the rays more divergent. 



