



CONTENTS OF VOLUME II, 



[Note. — For Analytical Index, see first Volume.] 



MATTER AND ITS PHYSICAL PROPERTIES page 17 



Divisibility. — Unlimited Divisibility. — Wollaston's Micrometric Wire. — Method of Making it. — 

 Thickness of a Soap-Bnbble. — Wings of Insects. — Gilding of Embroidery. — Globules of the 

 Blood. — Animalcules. — Their minute Organization. — Ultimate Atoms. — Crystals. — Porosity. — Vol- 

 ume. — Density. — Quicksilver passing through Pores of Wood. — Filtration. — Porosity of Hydro- 

 phane. — Compressibility. — Elasticity. — Dilatability. — Heat. — Contraction of Metal used to restore 

 the Perpendicular to Walls of a Building. — Impenetrability of Air. — Compressibility of it. — Elas- 

 ticity of it. — Liquids not absolutely Incompressible. — Experiments. — Elasticity of Fluids. — Aeriform 

 Fluids. — Domestic Fire-Box. — Evolution of Heat by compressed Air. — Inertia. — Matter incapable 

 of spontaneous Change. — Impediments to Motion. — Motion of the Solar System. — Law of Nature. 

 — Spontaneous Motion. — Immateriality of the thinking and willing Principles. — Language used to 

 express Inertia sometimes faulty. — Familiar Examples of Inertia. 



ELASTICITY OF AIR 39 



Exhausting Syringe. — Rate of Exhaustion. — Impossible to produce a perfect Vacuum. — Mechanical 

 Defects. — The Air-Pump. — Barometer-Gauge. — Siphon-Gauge. — Various Forms of Air-Pump. — 

 Pump without Suction-Valve. — Experiments with Air-Pump. — Bladder burst by atmospheric 

 Pressure. — Bladder burst by Elasticity of Air. — Dried Fruit inflated by fixed Air. — Flaccid Blad- 

 der swells by Expansion. — Water raised by Elastic Force. — A Pump cannot act in the Absence 

 of atmospheric Pressure. — Suction ceases when this Pressure is removed. — The Magdeburg Hem- 

 isphere. — Guinea and Feather Experiment. — Cupping. — Effervescing Liquors. — Sparkling of 

 Champagne, &c. — Presence of Air necessary for the Transmission of Sound. — The condensing 

 Syringe. — The Condenser. 



EFFECTS OF LIGHTNING 61 



Classification of the Effects of Lightning. — The sulphureous Odor developed by Lightning. — Cases 

 collected by M. Arago. — Nature of the Odor. — Chemical Changes operated by Lightning. — Nitric 

 Acid formed by the Electric Spark; also Ammonia and Nitric Acid produced during Thunder- 

 storms. — Fusion and Contraction of Metals. — Observations of the Ancients. — Franklin's cold 

 Fusion. — Evidence against cold Fusion. — Masses of Metal melted by Lightning. — Vitrefactions 

 and Fulgurites. — Heights at which Vitrefactions have been found. — Facts collected by M. Arago. 

 — Fulminary Tubes, or Fulgurites. — Characters of Fulgurites. — Variations dependent on the Na- 

 ture of the Soil where they are found. — Four Hypotheses to explain their Origin. — Their Forma- 

 tions in some Cases are recent.— Sand fused by artificial Heat into the State of the Fulgurites. — 

 Artificial Fulgurites formed by the Electrical Battery. — The further Condition essential to explain 

 the Origin of Fulgurites. — Recent Formation of Fulgurites observed. — Mechanical Ejects. — In- 

 stances of the Mechanical Action of Lightning. — The Action is exerted in all Directions. — Induc- 

 tive Action of Lightning. — M. Arago's Explanation of the Effect as due to Vaporization. — Objec- 

 tions to the Explanation. — Decompositions of the natural Electricities of Bodies. — Induction 

 between the Clouds and the Earth. — Upward Flashes and Mechanical Effects. — Arago's Explana- 

 tion. — Magnetic Effects. — To be explained in Electro-Magnetism. — Effects of conducting Bodies 

 on Lightning.— Conducting Properties of Metallic Bodies. — Lightning passing along Conductors 

 in Preference to Non-Conductors. — Protection afforded by conducting Bodies. — Lightning selects 

 conducting Bodies from among others. — Lightning Conductors should descend to a humid Soil. — 



