CONTENTS. xvii 



springs, 152. Expansion of pendulums ; Compensations for clocks, 153. Com- 

 pensations for watches ; Resistance of the air, 15*. Striking part ; Supports of 

 clocks ; Mutual influence of two clocks, 155. 



LECTURE XVIII. 

 ON RAISING AND REMOVING WEIGHTS, 156. 



Counteraction of gravitation; Levers, 156. Perrault's lever; Axis with a 

 winch ; Water whimsey ; Gin, 157. Capstan ; Double capstan ; Wheelvvork ; 

 String of buckets, 158. Pullies ; Inclined plane; Duke of Bridgwater's canal, 159. 

 Screws ; Cranes ; Walking wheels, 160. White's crane ; Weighing cranes ; Lewis; 

 Counterpoise for a chain ; Removing weights, 161. Porters ; Distribution of 

 weight: Simple dray, 162. Effect of agitation ; Oily substances; Rollers, 163. 

 Friction wheels ; Perrault's ropes ; Wheels of carriages, 164- . Magnitude of 

 wheels, 165. Line of draught; Conical wheels; Effect of springs, 166. Attach- 

 ment of horses ; Wheel ways, 167. String of baskets or carts, 168. 



LECTURE XIX. 



ON MODES OF CHANGING THE FORMS OF BODIES, 169. 



Compression ; Presses ; Effect of momentum ; Printing press, 169. Sugar mill ; 

 Oil mills ; Hammering; Hydrostatic press; Extension; Laminating machine, 170. 

 Glazier's vice; Wire drawing; Pottery; Glassblowing ; Percussion; Forges; 

 Goldbeating ; Coining, 171. Stamping; Penetration, 172. Pile driving engine ; 

 Sling; Bow and arrow, 173. Whip; Division; Cutting instruments; Slitting 

 mill; Lathes, 174. Boring; Agricultural instruments; Mining; Sawing, 175. 

 Stonecutting; Grinding; Polishing, 176. Trituration ; Powder mills, 177. Agi- 

 tation; Threshing machines ; Corn mills, 178. Kneading; Levigating; Demoli- 

 tion ; Bolt drawer; Burning, 179. Blasting, 180. 



LECTURE XX. 

 ON THE HISTORY OF MECHANICS, 180. 



Origin of the Grecian learning in Egypt ; Thales ; Ionian school ; Italian school; 

 Pythagoras, 181. Democritus ; Invention of the arch ; Archytas and Eudoxus, 

 182. Aristotle ; Foundation of Alexandria ; Epicurus, 183. Archimedes ; Siege 

 of Syracuse, 184, 185. Athenaeus ; Ctesibius, 185. Vitruvius ; Middle ages; 

 British manufactures, 186. Anglonorman and Gothic architecture, 187. Roger 

 Bacon ; Clocks ; Engraving and Printing, 188. Leonardo da Vinci ; Bacon Lord 

 Verulam ; Galileo; Napier, 189. Laws of collision; Hooke ; Barrow; Newton, 

 190. Followers of Newton, 191. Modern mathematicians and mechanics ; Time- 

 keepers ; Journals ; Royal Institution, 192. Future prospects ; Use of a catalogue 

 of references, 193. Table of the chronology of mathematicians and mechanics, ta 

 face p. 194. 



