574 Professor Tijndall [Jan. 22, 



qualities to the light-medium which would enable it to diflfer in its 

 mechanical action from the sound-medium was an idea too bold — 

 I might indeed say too repulsive — to the scientific mind to be seriously 

 entertained. Yet, deeply pondering the question, Young ww,s at 

 length forced to the conclusion that the vibrations concerned in the 

 propagation of light were executed at right angles to the direction of 

 the ray. By this assumption of transverse vibrations, which removed 

 all difficulty, Young also removed the ether from the class of aeriform 

 bodies, and endowed it with the properties of a semi-solid. 



Fresnel's memoir on Diffraction, upon which, as already stated, 

 Arago had reported, initiated a lasting friendship between the two 

 illustrious Frenchmen. They subsequently worked together. Fresnel, 

 the more adventurous and powerful spirit of the two, came indepen- 

 dently to the same conclusion that Young had previously enunciated. 

 But so daring did the idea of transverse vibrations appear to Arago — 

 so inconsistent with every mechanical quality which he could venture 

 to assign to the ether — that he refused to allow his name to appear 

 in conjunction with that of Fresnel on the title-page of the memoir 

 in which this heretical doctrine was broached. Still, the heresy has 

 held its ground, and the theory of transverse vibrations as applied to 

 the ether is now universally entertained. 



Fresnel died in the fortieth year of his age. 



Allow me to wind up this section of our labours by reference to 

 a German estimate of Young's genius. " His mind," says Helmholtz, 

 " was one of the most profound that the world has ever produced ; 

 but he had the misfortune of being too much in advance of his age. 

 He excited the wonder of his contemporaries who, however, were 

 unable to rise to the heights at which his daring intellect was accus- 

 tomed to soar. His most important ideas lay, therefore, buried and 

 forgotten in the folios of the Eoyal Society, until a new generation 

 gradiially and painfully made the same discoveries, and proved the 

 truth of his assertions and the exactness of his demonstrations." 



HiEEOGLTPHICAL EeSEAKCHES. 



Young's capacity and acquirements in regard to languages have 

 been already glanced at. As a classical scholar his reputation was 

 very high, and his Greek calligraphy was held to vie in elegance 

 with that of Person. A man so rounded in his culture could hardly 

 be said to have an intellectual bent ; but if he had one, the examina- 

 tion and elucidation of ancient manuscripts must have fallen in with 

 it. It is quite possible, however, that, had he not been disheartened 

 by the apparent success of Brougham, he would have clung more 

 steadfastly to physical science. However this may be, we now find 

 him in a new field. In October 1752 the first rolls of the papyri of 

 Hercnlaneum, wearing the asjiect of blackened roots, were discovered 



