The glass harmonica, also known as the glass armonica, glass harmonium, bowl organ, hydrocrystalophone, or simply the armonica or harmonica is a type of musical instrument that uses a series of glass bowls or goblets graduated in size to produce musical tones by means of friction and people thought that it made people insane in those days. Later Benjamin Franklin invented his mechanical version of the instrument in 1761, he called it the armonica.
Here is an example of spine chilling glass harmonica performance while you are reading the article.
Glass harmonica first presented by Irish musician Richard Puckeridge with water filled glasses in a show
in italian " Armonica" harmony means the simultaneous combination of tones that feels good when listening
But Why this instrument got forbidden ?
Human brain can't sense the sounds below 4000 Heartz but Glass harmonica creates sounds between 1000-4000 Heartz. Since the brain can't sense sounds below 4000 Heartz hearing problems occurs while listening the glass harmonica . The diffence between right and left ear spot causes Phase differences.