THE JEWS IN EUROPE. 205 



sounds that coalesce harmoniously. A well-trained ear may pick out 

 some of the overtones without the aid of resonators, and perceive in 

 the background a few duplicated sound-images ; but the great major- 

 ity of them are so faint that their presence can not be perceived apart 

 from each other, or from the fundamental to which they give character. 

 The rich combination of all stands out in strong musical relief, com- 

 pared with what each voice alone would yield, or with the sweet but 

 thin sound of a tuning-fork that sings forth the same fundamental pitch. 



This principle relates to the combination of sensations, whatever 

 may be the cause of dissimilarity among the components of the group. 

 We have not the data from which a binocular image can be graphic- 

 ally expressed as a curve, for the dissimilarity of the components is 

 not due to interference of waves of light. But the facts suggest kin- 

 ship between the modes of sensation in the two cases. The dissimilar 

 groups of light-images arouse sensations that are simultaneously con- 

 veyed to the brain, and the proper interpretation at once comes as the 

 product of past experience. All we can affirm is, that experience has 

 taught us to interpret retinal sensations which are slightly different in 

 the two eyes, as the signs of an external object possessing three dimen- 

 sions in space, when the images are produced upon parts of the con- 

 cave surfaces which bear to each other the relations that would be im- 

 posed by the presence of such an object if naturally viewed. Such 

 experience has been acquired by each of us individually, and probably 

 with exceeding rapidity in consequence of inherited tendencies. It is 

 therefore not necessary that the localization of what we see in the 

 stereoscope should be limited to cases of optic convergence, or the per- 

 ception of relief to those in which double images can be distinguished. 



Our discussion has led us from the domain of physics to the con- 

 fines of metaphysics. Explanations are at best only relative, and the 

 psychologist, the physiologist, and the physicist must join hands in 

 working out the problems of binocular vision. The progress made 

 during the last half-century invites the hope that much may yet be 

 accomplished before the next century brings us its morning greeting. 







THE JEWS IN EUROPE * 



By Dr. J. VON DOLLINGEE. 



' I. 



THE Academy celebrates to-day the birth of its royal head and 

 gracious protector. Such a festival is, first of all, devoted to 

 feelings the simplest, purest, and most elevating love, reverence, 



* Anniversary Address before the Academy of Sciences at Munich, delivered July 

 25, 1881. Translated^ Mr. W. M. Salter. 



