A key component of these devices was changed to be shaped like a rhomboid and was made to last much longer by Gowin Knight.  
A key component of these devices was changed to be shaped like a rhomboid and was made to last much longer by Gowin Knight.  The city of Amalfi erected a statue of Flavio Gioia, wrongly credited with introducing these devices to Europe.  The first of these devices may have been invented by Chinese jade (*) miners and were known as a sinan.  One type of these devices is placed on top of a leaf that itself floats in water.  The original purpose of a binnacle was to hold these devices.  Silva of Sweden began as a company that made highly accurate types of these devices.  A digital one of these things was added to the iPhone 3GS.  Edward Samuel Ritchie's liquid one of these devices improved their stability on ships.  In Han-era China, these things were used for divination and consisted of a "heaven plate" and a lodestone.  For 10 points, name these devices for finding magnetic north.
A key component of these devices was changed to be shaped like a rhomboid and was made to last much longer by Gowin Knight.  
magnetic compass [prompt on lodestone before mentioned]