111. SCRIBNER AND M’BERTY’S EXPERIMENT. SOURCE OF X-RAYS DETERMINED BY INTERCEPTION OF ASSUMED RECTILINEAR RAYS FROM THE CATHODE. _Elect. Eng._, N.Y., Apr. 8, ’96, p. 358; _Amer. Inst. Elec. Eng._, Mar. 25, ’96. _West. Branch._—Refer now solely to Fig. 1, S. and M.’s experiment. Notice the relative arrangement of the elements. First, the discharge tube with the cathode at the upper part and the phosphorescent spot opposite thereto; then below a thick lead plate with a single opening; then a second lead plate with two small openings placed laterally at such a distance that if there were rectilinear rays from the cathode they could not strike (by passing through the small hole), the covered photographic plate which was the next element in order. The description did not state that the photographic plate was covered, but the experimenters must have had the usual opaque cover upon it or else the luminous rays could have produced images. The developed plate showed two spots strongly acted upon and surrounded by portions which were less acted upon, the same as would be produced by light radiating from a surface as distinguished from a point. From the fact that they stated that the exposures were very long, it may be concluded also that the plates were covered by a material opaque to ordinary light. Measurement showed that the rays which produced the images came from the phosphorescent spot (§ 106, 109, 114, 131, 139) and not from the cathode directly by rectilinear propagation. [Illustration: S. & M.’S EXPERIMENT, FIG. 1. & 2. ]