Galileo Galilei the use of the compasses for 120 lire. In about 1593, Galileo constructed a thermometer, using the expansion and contraction of air in a bulb to move water in an attached tube. In 1609, Galileo was, along with Englishman Thomas Harriot and others, among the first to use a refracting telescope as an instrument to observe stars, planets or moons. The name "telescope" was coined for Galileo's instrument by a Greek mathematician, Giovanni Demisiani, at a banquet held in 1611 by Prince Federico Cesi to make Galileo a member of his Accademia dei Lincei. The name was derived from the
Adriaan Metius and developed a special form of Jacob's staff. In 1585, his father had estimated the ratio of a circle's circumference to its diameter, later called pi, to be approximately . Metius later published his father's results, and the value is traditionally referred to as Metius' number. The lunar crater Metius is named after him. In Vermeer's painting "The Astronomer" (1668), the book lying on the table has been identified as a 1621 second edition of Metius's "Institutiones Astronomicae Geographicae". It is opened to Book III, where "inspiration from God" is recommended for astronomical research along with knowledge of geometry and