THE. EARTH. 



A difficult Subject of Investigation. Form of the Earth. How proved Globular. Its Magnitude. 

 Its annual Motion. Elliptic Form of its Orbit. Proofs of its annual Motion from the Theory of 

 Gravitation. From the Motion of Light. The Earth's diurnal Motion. Inequalities of Day and 

 Night.-Weight of the Earth. Maskelyne's Experiment. Cavendish's Experiment. Their Ac- 

 cordance. Density of the Earth. The Season*. Calorific Effect of the Snn's Rays. Why the 

 longest is not the hottest Day. Why the shortest Day is not the coldest. The hottest Season takes 

 place when the Sun is farthest from the Earth. Proofs of the diurnal Rotation. Spheroidal Form 

 of the Earth proved by Theory and by Observation. 





