CONTENTS OF VOLUME II. 



9 



THE LATITUDES AND LONGITUDES PAGE 559 



Definition of the Equator and Poles. Northern and southern Hemispheres. Latitude of a Place 



Parallel of Latitude. Meridian of a Place. Longitude of a Place. Standard Meridian. Meth- 

 ods of determining Latitude and Longitude various. To find the Latitude. Methods applicable 

 in Observatories. At Sea. Hadley's Sextant. To determine the Longitude. How to find the 

 Time of Day at Land. At Sea. Use of Chronometers. Lunar Method of finding the Longi- 

 tude. Apparatus provided at Greenwich for giving the exact Time to Ships leaving the Port of 

 London. Method of determining Longitude by Moon-culminating Stars. 



THEORY OF COLORS , 573 



Refraction of a Ray of Light. At plane Surfaces. By a Prism. The Prismatic Spectrum. The 

 Decomposition of Light. Newton's Discoveries. Colors of the Spectrum. Brewster's Discovery 

 of three Colors. How three Colors can produce the Spectrum. Colors of natural Bodies. How 

 they are produced. 



THE VISIBLE STARS 583 



What occupies the Space beyond the Limits of the Solar System. Wide Vacuity between this 

 System and the Stars. Indications of this observable in the Motions of the Planets. Indications 

 in the Motions of the Comets. The immence Distance of the Stars proved by the Earth's annual 

 Motion. Observations made at Greenwich. Bessel's Discovery of the Parallax. The conse- 

 quent Distance of the Stars. Illustrations of the Magnitude 01 this Distance. The different 

 Orders and Magnitudes of the Stars. How accounted for. Why those of the lowest Magnitude 

 are most numerous. The real Magnitude of the Stars. The Telescope unable to magnify 

 them. Dr. Wollaston's Investigations of the comparative Brightness and Magnitude of the Stars 

 in relation to the Sun. Their stupendous Magnitude. Application of this to the Dog-Star. 



WATERSPOUTS AND WHIRLWINDS 597 



Character and Effects of Water-Spouts. Difference between Water and Land-Spouts. Land- 

 Spout at Montpellier. Land-Spout at Esclades. Columns of Sand on the Steppes of South 

 America. Meteor at Carcassonne. Meteor at Dreux and Mantes. Land-Spout at Ossonval. 

 Meteor witnessed and described by M. Peltier. Conversion of a Storm into a Land-Spout. 

 M. Peltier's Tables of Water-Spouts and Land-Spouts. Analysis of the above Tables. Water- 

 Spouts seen by Captain Beechy. Experimental Illustration of the Phenomena. Illustration 

 of the gyratory Motion of Water Spouts. M. Peltier's Deductions concerning Water Spouts. 

 Action of charged Clouds on light Bodies. Noise attending Water and Land-Spouts. Trans- 

 ition from direct to gyratory Motion. Effect of Induction on watery Surfaces. Disappearance 

 of Pools, &c. 



