EULOGY OX THOMAS YOU.NG. 119 



We miglit fairly be astonislietl that this admirable theory of vision, 

 this combiuatioii\so well framed when the most ingenious reasonings 

 and experiments lent each othei mutual support, did not occupy that 

 distinguished rank in the science of the country which it deserved. 

 But to explain this anomaly, must we necessarily recur to a, sort of 

 fotality ? Was Young then' really, as he sometimes described himself 

 with vexation, a new Cassandra, proclaiming incessantly important 

 truths which his ungrateful contemporaries refused to receive ? We 

 should be less poetical but more true, it seems to me, if we remarked 

 that the discoveries of Young were not known to the majority of those 

 who would have been able to appreciate them. The physiologists did 

 not read his able memoir, because in it he presumes upon more mathe- 

 maticfll knowledge than is usually attained in that branch. 



The physicists neglected it in their turn, because in oral lectures or 

 printed works the public demands little more at the present day than 

 superficial notions, which an ordinary mind can penetrate without difli- 

 culty. In all this, whatever our distinguished colleague may have 

 believed, we perceive nothing out of the ordinary course. Like all those 

 who sound the greatest depths of science, he was misunderstood by the 

 nmltitude ; but the applauses of some of the select few ought to have 

 recompensed him. In such a question we ought not to count the suf- 

 frages J it is more wise to weigh them.* 



INTERFERENCES. 



The most beautiful discovery of Young, that which will render his 

 name imperishable, was suggested to him by an object in appearance 

 very trivial — by those soap-bubbles so brilliantly colored, so light, 

 which when just blown out of a pipe become the sport of every imper- 



*Arago, iu assio-uino- the probable causes of the neglect of Young's speculations, 

 seems to fall short of his usual point and persi^icuity. It might be true that his 

 memoii- \Yas neglected by physiologists because it was mathematical, and by parity of 

 reason it might have been neglected by physicists and luathcmaticiaus as being physio- 

 logical. But it is surely no reason to say that it was neglected by physicists because 

 the public are superficial, &c. Young may have been in most of his speculations too 

 profound for the many ; but this particular instance of the structure of the eye and 

 theory of vision is, perhaps, of all his researches, that which can be the least open to 

 this charge. The snl)ject is not itself abstruse ; it is one easily understood by every 

 educated person, without mathematical atttainments ; and the point at issue was a 

 simple question of fact, requiriug no profound physiological kuowledge to ai)preciate 

 whether the crystalline has or has not a nuiscular structure capable of chaugiu"' its 

 convexity. The real state of the case seems to be very satisfactorily explamed by 

 Dean Peacock, (p. 36 et scq.,) from whose account, as well as from what has been since 

 written, it appears, after all that has been done both by Dr. Young and others, that 

 there is even at the present day considerable difterence of o[)iui()u ou the sul>ject. 



Perhaps the most comprehensive survey of the whole subject which recent investi- 

 gation has produced will be found in the paper of Professor J. D. Forbes iu the Edin- 

 burgh Transactions, vol. xvi, pt. i, 1845. After giving a summary view of preceding 

 researches, and adverting to the prevalent opinion among men of science that the true 

 explanation yet remains to be discovered, (most anatomists denying as a fact the exist- 

 ence of the mtisoilar structure which Young conceived ho had proved,) Professor Forbes 

 proposes as his own view of the cause the consideration of the remarkable variation in 

 density of the crystalline toward its central part ; coats of ditierent density, being dis- 

 Ijosed iu different layers, may be acted ou by the pressure of tlie humors of the eye 

 when the external action of the muscle compresses them, and thus increase the ciu'va- 

 ture of' the lens when tho eye is directed to a near object, the whole consistence, espe- 

 cially in the outer parts, being of a gelatinous or compressible nature, and the central 

 part more solid and more convex. Tluis uniform pressure ou the outer parts would 

 tend to make the outer jiarts conform more nearly to the more convex interior iiucleus. 



It may be added that many physiologists are of opinion that, after all, there does 

 not exist a sufficient compressive action on the ball of the eye to i^roduce the effect 

 supposed. — Tkaxslatok. 



