Morton, Edward Reginald, 1867- · New York : E.B. Treat & Co. · leaf 119
*» <i … Fig. 40. Eftect of Diaphragms. Diaphragms, by cutting off the stray rays from thewalls of the tube, etc., are necessary if sharp outlines areto be secured. The value of a diaphragm can be very readily demon-strated on the screen. Tn examining the chest, forinstance, the interposition o^ a metal…
