. American quarterly of roentgenology . he Lothian from Scotland. The Piriemakes one of a reflecting prism of peculiar form—a singleglass being inserted in the right-hand tube. At first this in-strument gave promise of being useful, until in practice, itwas found that not one person in four could successfully useit without preliminary practice; furthermore, its constructionwas such that unless the interpupilary distance was quitenormal, one could not see into the eye-pieces at all. The Lo-thian (popular in England for viewing small stereoscopic pic-tures) is optically similar to our small hand
. American quarterly of roentgenology . he Lothian from Scotland. The Piriemakes one of a reflecting prism of peculiar form—a singleglass being inserted in the right-hand tube. At first this in-strument gave promise of being useful, until in practice, itwas found that not one person in four could successfully useit without preliminary practice; furthermore, its constructionwas such that unless the interpupilary distance was quitenormal, one could not see into the eye-pieces at all. The Lo-thian (popular in England for viewing small stereoscopic pic-tures) is optically similar to our small hand stereoscopes;both types using lenticular prisms of various focal length. Forthis reason, as before stated, they are useful only in nearwork with small prints, or for lantern-plate transparencies. Threlkeld-Edwards : Stereoscc pe J ) The result of ten months work, with all the available mod-els, and experimenting with various combinations of lenses,prisms and mirrors, is the little instrument herewith describedand illustrated. - 3 ^~. ficrjr Illustrating theory and use of Dr. Threlkeld-Edwards Stereoscope 194 American Quarterly of Roentgenology As will be seen by referring to the photographs and the line-drawing, the instrument itself is extremely simple in designand construction, and the essayist claims no special creativeoriginality in its evolution. The optical principle involved(See Fig. 1) is properly orthodox and respectably well known—even the architecture is reminiscent of an existing and popu-lar type of hand-stereoscope. Nevertheless, this little stereo-scope is, in action, unlike any of its prototypes now used inexamining binocular pictures to give them the plastic or per-spective effect, so far as my knowledge goes. While it is quite possible that instruments of this type andcontraction may have been made before, and even be in useat the present time, it is certain that there is nothing like itupon the market, or available for general use, anywhere. Three of the
Size: 1056px × 2367px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bo, bookcentury1900, bookdecade1910, bookidamericanquarterl03amer
