110. Apparent Diffraction Really Due to STINE Penumbral Shadows. 110_a_. Non-diffraction. PERRIN 159_a_. Non-Refraction 111. Source of X-rays Tested by SCRIBNER and Interceptance of Assumed Rectilinear M’BERTY Rays from the Cathode. 112. Source of X-rays on the Inner Surface SCRIBNER and of the Glass Tube Determined by M’BERTY, Pin-hole Images. PERRIN 112_a_. Anode Thought to be the Source. Cause DE HEEN of Error Suggested. 113. Pin-hole Pictures by X-rays Compared LODGE with Pin-hole Images by Light to Determine the Source. X-rays Most Powerful when the Anode is the Part Struck by the Cathode Rays. 114. Valuable Points Concerning Electrical LODGE Apparatus Employed. 115. X-rays Equally Strong during Fatigue of LODGE Glass by Phosphorescence. 116. Area Struck by Cathode Rays Only an ROWLAND, Efficient Source when Positively CARMICHAEL, Electrified. and BRIGGS 117. Transposition of Phosphorescent Spot SALVIONI, and of Cathode Rays without a Magnet. ELSTER, GEITEL, and TESLA 117_a_. Molecular Sciagraphs in a Vacuum Tube. HAMMER and FLEMING CHAPTER X. 118. X-rays Begin before Striæ End. EDISON and THOMSON, E. 119. Reason why Thin Walls are Better than EDISON Thick. 120. To Prevent Puncture of Discharge Tube EDISON by Spark. 121. Variation of Vacuum by Discharge and by EDISON Rest. 122. External Electrodes Cause Discharge EDISON through a Higher Vacuum than Internal. 123. Profuse Invisible Deposit from Aluminum EDISON and Cathode. MILLER 124. Possible Application of X-rays. EDISON and Fluorescent Lamp. FERRANTI 124_a_. Greater (?) Emission of X-rays by PILTCHIKOFF Easily Phosphorescent Materials. 125. Electrodes of Carborundum. EDISON 126. Chemical Decomposition of the Glass of EDISON the Discharge Tube Detected by the Spectroscope.