Curvilinear motion, 47, 72. Cylinder, 52. D. Day, 78, 105, 106. Degrees, 44, 94, 99, 169, 170. of latitude, 94, 112. of longitude, 94, 112. Density, 16. Diagonal, 47. Diameter, 94. Discords, 155. Diurnal, 78. Divergent rays, 175, 177. Divisibility, 10, 12. E. Earth, 18, 70, 84, 88, 95. Echo, 154. Eclipse, 110, 159. Ecliptic, 86, 92, 99. Elasticity, 41. Elastic bodies, 28, 40. fluids, 28, 41, 118, 136. Ellipsis, 75. Equinox, 100, 107. precession of, 107. Equator, 92, 99. Essential properties, 10. Exhalations, 13. Extension, 10, 11. Eye, 166, 195. F. Fall of bodies, 24, 27, 31. Figure, 10, 12. Fluids, 118, 128. elastic, 28, 41, 118, 136. equilibrium of, 120, 122, 132. non-elastic, 119. pressure of, 121. Flying, 40. Focus, 176. of concave mirrors, 177. of convex mirrors, 175, 177. of a lens, 184. imaginary, 176. virtual, 176. Force, 33. centrifugal, 49, 72, 95, 115. centripetal, 49, 72. projectile, 47, 49. of gravity, 47, 49. Fountains, 135. Friction, 68, 69, 135. Frigid zone, 93. Fulcrum, 54. G. General properties of bodies, 10. Georgium Sidus, 85. Glass, 183. burning, 188. refraction of, 183. Gold, 119, 126. Gravity, 18, 23, 78, 97. H. Harmony, 155. Heat, 16, 29, 103. Hemisphere, 92, 100. Herschel, 85. Hydraulics, 118. Hydrometer, 128. Hydrostatics, 118. I. Image on the retina, 165, 172. reversed, 167. in plain mirror, 172. in concave do. 175. in convex do. 175. Impenetrability, 10. Inclined plane, 54, 66. Inertia, 10, 14, 32. Inherent properties, 10. Juno, 84. Jupiter, 85. L. Lake, 133, 135. Latitude, 94, 112. Lens, 184. concave, 184. convex, 184. meniscus, 184. plano-concave, 184. plano-convex, 184. Lever, 54, 55. first kind, 58. second kind, 60. third kind, 60. Light, 157. pencil of, 158. of the moon, 162, 163. absorption of, 188. reflected, 160. refraction of, 179. Liquids, 118. Longitude, 94, 112. Luminous bodies, 157. Lunar month, 108. eclipse, 110. M. Machine, 54, 66. Magic lanthorn, 203. Mars, 84. Matter, 10, 13. Mechanics, 32. Mediums, 157, 180. Melody, 156. Mercury, (planet) 83, 85, 114. Mercury, or quicksilver, 16, 140, 141. Meridians, 93. Microscope, 200. single, 200. double, 200. solar, 202, 203. Minerals, 12. Minutes, 94. Momentum, 38, 56. Monsoons, 149. Month, lunar, 108. Moon, 78, 79, 80, 82, 85. Moonlight, 162, 163. Motion, 14, 32, 36. accelerated, 36. axis of, 48. centre of, 48, 55. compound, 46. curvilinear, 47, 49. diurnal, 78. perpetual, 35. retarded, 35. reflected, 43. uniform, 34. Mirrors, 172. axis of, 176. burning, 177. concave, 174, 176, 209. convex, 174, 175. plane or flat, 172. reflection of, 173. N. Neap tides, 116. Nerves, 166. auditory, 151, 166. olfactory, 166. optic, 164, 166. Night, 78. Nodes, 110. O. Octave, 156. Odour, 13. Opaque bodies, 157, 158. Optics, 157. Orbit, 86. P.