Prof. Wallace on the Invention of the Pantograph. 419 



the original. Of these, a sheet of semi-transparent tracing paper 

 laid on the subject to be copied, is one of the most simple and 

 elegant. On this, the engraver may make an outline of a subject 

 which he means to transfer to his copperplate. If he set no va- 

 lue on the original design, he may dispense with the transparent 

 paper ; and having made a trace with black lead along the lines 

 to be copied, he may render them visible on the copper by the 

 pressure of the rolling-press. 



Another elegant way of making a copy is by means of a tra- 

 cing glass. This, fixed in a frame, is placed in a sloping direc- 

 tion like a writing desk : the sheet to be copied is laid on the 

 glass, and the paper on which the copy is to be made above it : 

 a strong light, either natural or artificial, is directed upwards 

 through the glass, while the surface on which the copy is to be 

 made is skreened from the light. The fines to be copied are 

 thus made visible through the two sheets, and a trace is made on 

 the uppermost by carrying a point over them. 



If a subject is to be diminished or enlarged, none of these 

 methods will apply. Now this is by far the most common case 

 at the present time, when numberless Encyclopaedias, Atlases, 

 and other works illustrated by figures, are in progress of publica- 

 tion, the materials of which are, for the most part, taken from 

 writers of established eminence. 



It may be supposed that attempts must long ago have been 

 made to furnish the various classes of artists with instrumental 

 aid. Tn investigating this subject, however, I did not find that 

 the mechanical contrivances for copying on an enlarged or redu- 

 ced scale, had been numerous or considerably different, or that 

 their application can be traced to a very remote period. There 

 is a well known instrument called the Pantograph : this appear- 

 ing to have been the earliest, and that from which all the others 

 have been imitated, I was induced to look into its history ; I 

 found it figured and described by various writers, who yet have 

 given no indication of its inventor. In a work called " Geome- 



VOL. XIII. PART II. 3 h 



