Eureka (word) "Eureka! Eureka!" after he had stepped into a bath and noticed that the water level rose, whereupon he suddenly understood that the volume of water displaced must be equal to the volume of the part of his body he had submerged. (This relation is "not" what is known as Archimedes' principle—that deals with the "upthrust" experienced by a body immersed in a fluid.) He then realized that the volume of irregular objects could be measured with precision, a previously intractable problem. He is said to have been so eager to share his discovery that he leapt out of his bathtub
Surprised by Joy Surprised by Joy Surprised by Joy: The Shape of My Early Life is a partial autobiography published by C. S. Lewis in 1955. Specifically, the book describes the author's conversion to Christianity which had taken place 24 years earlier. Lewis' purpose in writing was not primarily historical. His aim was instead to identify and describe the events surrounding his accidental discovery of and consequent search for the phenomenon he labeled "Joy", his best translation of the idea of "Sehnsucht" (). This "Joy" was so intense for something so good and so high up it could not be explained with words.