INDEX 



235 



Motor, electric, 162, 163. 

 Musical, instruments, 100 ; tones, 

 104, 105. 



Naphtha engine, 89. 

 Newton's laws of motion, 46. 

 Nitrates, 186, 195. 

 Nitric acid, 186. 

 Nitrogen, 195, 210, 218. 

 Nitroglycerin, 218. 

 Noise, 102. 



Ohm, 146. 



Oils, 208. 



Opaque bodies, 111. 



Ores, 185, 188. 



Overtones, 105. 



Oxidation, 225, 226. 



Oxides, 187, 188, 225. 



Oxygen, 189, 192, 210, 225, 226. 



Paper, 214. 



Parallel arrangement, 145. 



Pendulum, 57, 58. 



Penumbra, 112. 



Percussion, 67. 



Permanent magnet, 151, 158. 



Petroleum, 188, 217. 



Pewter, 188. 



Phosphorus, 196. 



Photographic camera, 122. 



Physical changes, 171. 



Physics, scope of, 2. 



Physiological effects of electricity, 



131. 



Pitch, 103 ; limiting, 104. 

 Platinum, 14. 

 Poles, in a cell, 142 ; magnetic, 



151; of the earth, 153. 

 Porcelain, 212. 



Pores, 9, 14. 



Porosity, 14. 



Potassium, 199; compounds, 199. 



Potential, electrical, 130, 132, 138. 



Power, 60; electrical, 146 ; horse, 

 60. 



Pressure, atmospheric, 32-39 ; ef- 

 fect of, on boiling point, 74 ; 

 fluid, 24 ; liquid, 24 ; transmis- 

 sion of, 30. 



Prism, 119, 126. 



Prismatic colors, 126. 



Propeller, screw, 49. 



Proteids, 189, 219. 



Pulley, 61, 62. 



Pump, air, 42 ; force, 38 ; lifting, 

 37 ; steam, 39. 



Push button, 144. 



Quality of tones, 104, 106. 

 Quartz, 201. 



Radiant energy, 83. 



Radiation, heat, 82, 83, 108 ; light, 



108-110. 



Radicals, 183, 186. 

 Rain, 76, 202. 

 Rainbow, 127. 

 Rays, light, 109. 

 Reaction, 48, 55. 

 Reflection, of light waves, 112, 



113 ; of sound waves, 97, 98. 

 Reflector, 114. 

 Refraction, 117, 118; cause of, 



119; use of, 120, 121. 

 Reservoir, 26. 

 Resistance, to electric current, 132, 



144 ; unit of, 146 ; uses of, 145. 

 Resonance, 99. 

 Resonators, 99, 100. 



