. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. ted,with the most elaborate electric-light apparatus, at what areconsidered the very head-quarters and principal arenas ofscientific exposition, in a manner inferior to what I had beenaccustomed to obtain with only oxy-hydrogen principles are the essential key to the whole of whatfollows; and both excellence of apparatus, and success inusing it, depend upon their being thoroughly grasped, in thefirst place by the optician, and in the second place by theoperator who uses th
. Optical projection : a treatise on the use of the lantern in exhibition and scientific demonstration. ted,with the most elaborate electric-light apparatus, at what areconsidered the very head-quarters and principal arenas ofscientific exposition, in a manner inferior to what I had beenaccustomed to obtain with only oxy-hydrogen principles are the essential key to the whole of whatfollows; and both excellence of apparatus, and success inusing it, depend upon their being thoroughly grasped, in thefirst place by the optician, and in the second place by theoperator who uses the apparatus which the other has con-structed. CHAPTER II THE PARTS OP A LANTERN A lantern is an optical apparatus so arranged, with all itsparts approximately fixed in their places, that pictures orapparatus can be exhibited on a screen with the least and mostconvenient manipulation. In this place we will consider onlythe exhibition lantern, for the projection of slides or diagrams,leaving other apparatus for separate consideration in achapter devoted to experimental lanterns. 14 OPTICAL PROJECTION. Fig. 8 7. Parts of a lantern.—The diagram (fig. 8) of one of thesimplest forms of lantern, once general, but now generally confined to mere toy instrumentsconveniently represents the es-sential parts, which we will con-sider singly. These are (1) thelight l, which may or may notbe supplemented by a reflectingmirror m. This, as it is theoriginal source from which allillumination is derived, whilethe word light may need tobe used in other senses, it willbe convenient to distinguish asthe radiant; and as it forms no part of the lantern itself, andvarious kinds of radiants are often employed in turn in the samelantern (as when an experiment is worked out in a small waywith a lamp, and afterwards publicly performed by the oxy-hydrogen light), we will postpone it for treatment separately,and pass on here to other details. These are (2) the lantern-body b, with its chimney or heat-vent.
Size: 1530px × 1633px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwrightle, bookcentury1900, bookdecade1900, bookyear1906
