Electroscope is the instrument that has the ability to detect the presence of an electric charge. Although electroscope has the power to measure the amount of charge, but for a perfect measurement the electrometer is used. Around the year 1600, electroscope was discovered by William Gilbert he British physician. This is a pretty primitive but highly effective instrument in regards to detecting the presence of electric charges. Two basic but effective electroscopes are the gold-leaf electroscope and the pith-ball electroscope.