the earth its shape, size, weight and spin

action amount angle appear attraction axis balance base body calculated carried centre centre of gravity circle clock common consider continue density describe determined diameter direction distance Earth effect equal equator exactly experiment feet figure fixed flat followed force further give globe gradually greater horizon inch increase later length less light mass matter mean measured meridian method miles million month Moon motion mountain move move round nearly observed once opposite orbit pendulum plane pole position pound present probably Prof proportional pull radius represented result rise rotation round seen shape shown side sky pole speed sphere spin star station suppose surface swing taken telescope temperature tides tilt triangle true turn vertical vibration weight whole wind wire