M. Aivigo oil the E^yjpllan Hieroglijpkical Writings. 47 



invention, and when he advanced that they had only been em- 

 ployed in the transcription of proper names, and those proper 

 names only which were foreign to Egypt. 



M. de Guignes and especially M. Etienne Quatreraere have, 

 on the contrary, established a fact of the greatest importance, 

 which the reading of the inscriptions of the Pharaohs has cor- 

 roborated by irresistible proofs, since they have pointed out 

 that the present Coptic language is the same as that of the an- 

 cient subjects of Sesostris ! 



And now I have adduced the facts, and may therefore limit 

 myself to establish, by some short observations, the consequences 

 which appear to me to result from them. Discussions about prio- 

 rity, even under the influence of national prejudices, would never 

 become embittered, if it were possible to determine them by fixed 

 rules ; but in one case the first idea is every thing, whilst in 

 another the details offer the principal difficulties, and some- 

 times the merit seems to consist less in the formation of a 

 theory, than in its demonstration. These reflections shew how 

 much the selection of the point whence the subject is viewe<l 

 will lead to a capricious result, and how much influence it will 

 likewise have upon the ultimate conclusion. To escape from 

 this embarrassment, I have sought for an example in which 

 every one would agree; — in which the parts performed by the two 

 claimants to the discovery, might be as near as possible assimi- 

 lated to those performed by Young and Champollion. This 

 example, I think, I have found in the question of interferences,* 

 even when, in the hieroglyphic discussion, we entirely lay aside 

 the citations which were taken from the memoir of M. de 

 Guignes. 



Hooke had in truth affirmed before Dr Young, that lumi- 

 nous rays interfere, as Dr Young had supposed before Cham- 

 pollion that the Egyptian hieroglyphics are sometimes phonetic. 

 Hooke did not directly prove his hypothesis ; and the proof of 



" Under the name o£ interference is understood a very remarkable action of 

 the rays of light, in virtue of which two of these rays, at their point of cross- 

 ing, may sometimes be imited, and sometimes may completely destroy each 

 other. By this law of interference, therefore, the optician arrives at a result 

 which is almost incredible ; he may produce a total ohscurilp by addxny light to 

 light ! 



