and Description of the Eidograph. 429 



known ; for besides occasional applications to the construction of 

 enlarged maps and scientific diagrams, exhibited in the meetings 

 of this Society, and to other purposes of public utility, it has 

 been extensively employed by some engravers in constructing 

 drawings for the plates of literary undertakings, and in particu- 

 lar, the seventh edition of the Encyclopaedia Britannica, now in 

 course of publication ; to the anatomical engravings of which, as 

 well as to those of other works of a like kind published in Edin- 

 burgh, it has given a degree of perfection much beyond what could 

 have been attained without its aid. 



I am sorry to have reason to say, that at least one imitation 

 of my instrument has been pressed on public attention, in oppo- 

 sition to mine, which, for an obvious reason, has been disparaged 

 by comparison with the imitation. I possess, however, in wri- 

 ting the testimony of competent judges that the defects alleged 

 to be in my instrument really did not exist. In fact, the imita- 

 tion is a modification of the first form that occurred to me, but 

 which was abandoned for a better. My case, however, is no 

 worse than that of many inventors : their labours have frequent- 

 ly been imitated after they have been at great pains and expense 

 in bringing them to some degree of perfection. 



The Eidograph has been shewn to every ingenious person 

 who has visited me since 1821, amongst whom have been many 

 foreigners. This has been done in order to spread a knowledge 

 of the invention, and to make it, if possible, useful to society ; and 

 I have had the satisfaction of knowing that an imitation of it has 

 been publicly exhibited amongst works of ingenuity in Russia 

 by a British officer, who, however, had the candour to acknow- 

 ledge to my friend who saw it, that it really was an imitation of 

 my instrument. 



I shall now state some of the advantages which the graphic 

 art may derive from the Eidograph. 



1. The instrument is applicable to the copying and reducing 

 of very nice works of design ; for example, the lineaments of a 

 portrait. Indeed, it has actually been applied to the tracing re- 



3i2 



