The Art of projection and complete magic lantern ... - Yesterday Image

—— ————114Pamphengos lamp with the microscope attachment, suitable objects suchas sheeptick, proboscis of fly, head of a silkworm, etc., may be magnifiedup to two, and some three feet and amplified to half this again, makingan image of four to five feet. A tracing paper screen is best suited forthis purpose, and of course the class must be very close to the medium.LANTERN PROJECTING MICRO POLARISCOPE.Fig. 55-Fig. 55 illustrates this instrument which has all the latest improvementsmade up to the present time and has the polarizing prisms fitted,so that nearly all the experiments both in polarized light and projectioncan be shown to the class without in any way altering the instrument, avery great advantage to the demonstrator.Reference to Fig. 55, shows (A) cells containing condensers, one ofwhich is fitted in cell upon a moveable rack work. (C) by which meansthe amount of divergence of rays can be altered, this arrangement is foruse with electric light, when the oxyhydrogen is used, the third lens (A^)marked for "lime light only" must be added. (B) Alum trough. (D)polarizing prism made to rotate by means of milled head, this is shownin drawing thrown out of position, and is so placed when the ordinaryprojection microscope is in use, the aperture of body being coveredby a moveable lid. {E) rack work adjustment for substage condensersand all apparatus used behind the object. (F) substage condenser.(G) mechanical rotating stage having ^" motion in rectangulardirections and is divided to 360 for use in crystalography. —( H) objectglass holder on rack work which admits of focussing the differentobjectives.— (Z) fine adjustment by means of t^o thread screw, thisadmits of the most delicate manipulation and is indispensable whenhigh power objectives are in use. (K) analyzing prism rotating mountalso divided to 360°. — (/) dovetail slot in object glass holder tocarry the quarter wave plate and Kleins quartz immediately behind theobjective.