184 ANNUAL OF SCIENTIFIC DISCOVERY. 



take consecutively, all round, the various outlines of each of 24 

 photographs. This is done in the following manner : The 24 

 photographs are placed in their proper order, in the outer circle of 

 a large vertical wheel, which can revolve at will merely by the im- 

 pulse of the hand ; so that each photograph can be placed, as long 

 as and whenever it is necessary, before the glass of a magic lantern ; 

 and the image of this photograph is projected upon a screen of ground 

 glass, at the distance which will give the desired dimension. The 

 modeler, having prepared his block of clay, and placed it close to th 

 ground glass, on a stand capable of turning upon its axis, holds in 

 his hands an ingenious instrument known as the pantograph, and 

 used extensively (before it was in part superseded by photography) 

 for enlarging or reducing, or copying upon the same scale, plans and 

 drawings, maps and diagrams. It consists of a series of bars of wood 

 or metal, jointed together so as to form a system of " similar trian- 

 gles ;" one of the bars carries at its extremity a tracing point or style, 

 and another a pen or pencil, the whole turning freely on a center car- 

 ried by a third bar. When the style is guided over the outline of a 

 drawing, the pencil moves with a perfectly similar motion over a sheet 

 of paper placed beneath it, and so produces a perfect fac-simile of the 

 original. Its application to photo-sculpture is as follows : Photograph 

 No. 1 is placed in a magic lantern, and an enlarged image of it pro- 

 jected upon a screen. Near to this screen is a small circular table, 

 turning upon a pivot, and divided round its circumference into 24 

 parts. Upon this little table is placed a block of modeler's clay, 

 of sufficient size to allow of a bust or statuette of the required dimen- 

 sions being cut from it ; and between it and the screen is mounted a 

 large pantograph, furnished at one end with the customary style or 

 tracer, but with a sharp tool or cutter occupying the place of the pen 

 or pencil. Photograph, pantograph, and clay block being adjusted to 

 their proper positions, the operator carefully guides the style over the 

 outline of the enlarged photograph, and the cutting tool, exactly fol- 

 lowing every motion of the style, cuts the clay into a profile exactly 

 corresponding to that of the photograph, and hence exactly similar 

 to the contour of the original model or sitter as seen from the point 

 occupied by camera No. 1. When this is done, the next photograph 

 is brought before the magic lantern, the block of clay is turned -^ of 

 the whole circle .marked on its stand, another profile is imparted 

 by the pantograph to the block of clay, and so on until the block has 

 received all round the 24 outlines of the 24 photographs. The oper- 

 ation is finished as far as it relates to the employment of the photo- 

 graphs. The bust or the statuette produced by this means is a like- 

 ness which, although in a somewhat uneven state, no one can mistake. 

 It is now necessary to smooth by hand, or bv a tool, all the slight 



*' " V ^J 



roughness produced by the various cuttings, and to soften down and 

 blend the small intervals between the outlines or profiles. 



This last operation requires the assistance of an artist, and is the 

 only part of the whole process that demands any more skill than is re- 

 quired in the most ordinary mechanical operations. The time occu- 

 pied is wonderfully short, compared with the tedious process of model- 

 ing a bust from the life, to say nothing of the disagreeable operation, 

 often resorted to, of taking a plaster cast of the face to serve as a 



