14 



CONTENTS OF VOLUME II. 



THE PULLEY page 269 



Cord. — Sheave.— Fixed Pulley.— Fire-Escapes.— Single moveable Pulley. — Systems of Pulleys — 

 Smeaton's Tackle. — White's Pulley. — Advantage of. — Runner. — Spanish Bartons- 



THE INCLINED PLANE, WEDGE, AND SCREW 281 



Inclined Plane. — Effect of a Weight on. — Power of. — Roads. — Power oblique to the Plane. — Plane 

 sometimes moves under the Weight. — Wedge. — Sometimes formed of two inclined Planes. — 

 More powerful as its Angle is acute. — Where used. — Limits to the Angle. — Screw. — Hunter's 

 Screw. — Examples. — Micrometer Screw. 



EBULLITION 295 



Process of boiling. — Vaporization and Condensation. — Latent Heat of Steam. — Experiments of 

 Black. — Effect of atmospheric Pressure on the boiling Point. — Ebullition under increased Pressure 

 — under diminished Pressure. — Relation between the Barometer and boiling Point. — Effect of the 

 Altitude of the Station of the boiling Point. — Elasticity of Steam.— Its Lightness.— Sum of the latent 

 and sensible Heat always the same. — Effect of the Compression of Steam without Loss of Heat. — 

 Steam cannot be liquefied by mere Pressure. — Boiling Points and latent Heat of other Liquids. — 

 Condensation of Vapor. — Principle of the Steam-Engine. — Nature of permanent Gases. — Examples 

 of the Application of the Properties of Steam. 



COMBUSTION 319 



Flame produced by chemical Combination. — Supporters of Combustion and Combustibles. — Oxygen 

 chief Supporter. — Heat of Combustion. — Flame. — Its illuminating Powers. — Combustion without 

 Flame. — Property of spongy Platinum. — Table of Heat evolved in Combustion. — Theory of La- 

 voisier. — Of Hook and others. — Electric Theory. 



HOW TO OBSERVE THE HEAVENS 329 



Interesting Nature of the Subject. — Diurnal Rotation. — Circumpolar Stars. — Ursa Major. — Forms 

 of the Constellations. — The Pointers. — The Pole-Star. — Cassiopeia. — Capella. — The Swan. — 

 Equatorial Constellations. — Orion. — Sirius, or the Dogstar. — Aldebaran. — Procyon. — Auriga.— 

 Columba. — Herschel's Observations on Sirius. — Dr. Wollaston's Observations. — Aspect of the 

 Heavens at different Seasons of the Year. — Uses of the Celestial Globe. — To Ascertain the 

 Aspect of the Heavens on any Night — at any Hour. — Effect of the Telescope on Fixed Stars. 

 — Relative Brightness of the Stars. — Theory of refracting and reflecting Telescopes, as applied 

 to the Stars. — Manner in which Sir W. Herschel applied it. — Method of estimating the Bright- 

 ness of small Stars. — Method of observing variable Stars. — Double Stars. — Description of the Mi- 

 crometer. 



THE STELLAR UNIVERSE— first lecture 355 



Range of Vision. — Augmented by the Telescope. — Periodic Stars. — Examples of this Class. — Vari- 

 ous Hypotheses to explain these Appearances. — Their Insufficiency. — Temporary Stars. — Re- 

 markable Examples of this Class. — These may possibly be periodic Stars. — Double Stars. — Their 

 vast Number. — They are physically connected. — Telescopic Views of them. — How they may in- 

 dicate the annual Parallax. — Researches of Sir W. Herschel. — Discovery of the orbitual Motions 

 of double Stars. — Binary Stars. — Extension of Gravitation to the Stars. — Their elliptic Orbits dis- 

 covered. — Effects of double and colored Suns. — Proper Motions of the Stars. — Probable Motion 

 of the Solar System. — Analysis of its Effects. — Suggestion of Mr. Pond. — Independent Motions of 

 the Stars. — Proper Motions of double Stars. — Probable Amount of the real Motions of the Stars. 



THE STELLAR UNIVERSE— second lecture 375 



Form and Arrangement of the Mass of visible Stars. — Sir W. Herschel's Analysis of the Heavens. 

 — The Milky Way. — The vast Numbers of Stars in it. — Form and Dimensions of this Mass of 

 Stars. — Nebulae and Clusters. — Various Forms and Appearance of Nebulas. — Great Nebula in 

 Orion. — Megallanic Clouds. — Planetary Nebulae. — Vast Number of Nebulae. — Herschel's Cata- 

 logue. — Structure of the Universe. — Laplace's nebular Hypothesis. — Examination of its moral 

 Tendency. 



THE STEAM-ENGINE— first lecture 397 



The Steam-Engine a Subject of popular Interest. — Effects of Steam. — Great Power of Steam. — 

 Mechanical Properties of Fluids. — Elastic and inelastic Fluids.— Elasticity of Gases. — Effects of 

 Heat. — Savery's Engine. — Boilers and their Appendages. — Working Apparatus. — Mode of Op- 

 eration. — Defects of Savery's Engine. — Newcomen and Cawley's Patent. — Accidental Discovery 

 of Condensation by Injection. — Potter's Invention of the Method of working the Valves. — His Con- 

 trivance improved by the Substitution of the Plug-Frame. 



THE STEAM-ENGINE— second lecture 417 



Mechanical Force of Steam. — Facts to be remembered. — Watt finds Condensation in the Cylinder 

 incompatible with a due Economy of Fuel. — Conceives the Notion of Condensing out of the Cyl- 

 inder. — Discovers separate Condensation. — Invents the Air-Pump. — Substitutes Steam Pressure 

 for Atmospheric Pressure. — Invents the Steam Case or Jacket — His first Experiments to realize 

 these Inventions. — His Experimental Apparatus. — His Models at Delft House. — Difficulties of 

 bringing the improved Engines into Use. — Watt employed by Roebuck. — His Partnership. — His 

 first Patent. — His Single- Acting Engine. — Discovery of the Expansive Action of Steam — Its Me- 

 chanical Effects. — Its Variable Action. — Methods of Equalizing it. — Its extensive Application in 

 the Cornish Engines. — Extension of the Steam-Engine to Manufactures. — Attempts of Papin, 



\ Savery, Hull, Champion, Stewart, and Washborough. — Watt's second Patent. — Sun-and-Planet 



, Wheels. — Valves of Double- Acting Engine. 



