 | Medicine - 1879 - 612 pages
...Eye," in an appendix thereto, in three, as follows: I. The eye must be sufficiently illuminated. II. The eye of the observer must be placed in the direction of the emergent rays. III. These emergent rays must be changed from their convergence, and rendered divergent... | |
 | John Soelberg Wells - Eye - 1883 - 922 pages
...Konigsberg, and since of Heidelberg [and now Professor of Physics in the University of Berlin. — B.], was the first to discover the reason why the retina...chamber, the light of a lamp was allowed to fall on a well-polished plate of glass in such a manner that the rays reflected therefrom entered the eye to... | |
 | Medicine - 1879 - 624 pages
...Eye," in an appendix thereto, in three, as follows: I. The eye must be sufficiently illuminated. II. The eye of the observer must be placed in the direction of the emergent rays. III. These emergent rays must be changed from their convergence, and rendered divergent... | |
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The problem was threefold : the observed eye must be sufficiently illuminated ; the eye of the observer must be placed in the direction of the emerging rays ; and these must themselves be changed from their convergence, and rendered divergent or parallel. 