Pendulum the pendulum could be used to measure the force of gravity. During his expedition to Cayenne, French Guiana in 1671, Jean Richer found that a pendulum clock was minutes per day slower at Cayenne than at Paris. From this he deduced that the force of gravity was lower at Cayenne. In 1687, Isaac Newton in "Principia Mathematica" showed that this was because the Earth was not a true sphere but slightly oblate (flattened at the poles) from the effect of centrifugal force due to its rotation, causing gravity to increase with latitude. Portable pendulums began to be taken on voyages
SS City of Manchester (1851) SS City of Manchester (1851) The SS "City of Manchester" was an iron-hulled single screw liner built 1851 by Tod & McGregor, Glasgow, Scotland and the second such ship owned by the Inman Line (officially the Liverpool and Philadelphia Steam Ship Company). It was an improved version of their first ship "City of Glasgow" which had been launched a year earlier. Steerage passengers were carried beginning in 1852. The "City of Manchester" was chartered to the French government during the Crimean War, and resumed Inman voyages in 1856. She departed London for Calcutta 24 August 1857 as a transport as