GALILEI, Galileo (1564-1642). Mathematical Discourses concerning Two New Sciences relating to Mechanicks and Local Motion in Four Dialogues. [translated by Thomas Weston]. London: J. Hooke, 1730.

“To give us the science of motion, God and Nature have joined hands and created the intellect of Galileo.” (Fra Paolo Sarpi (1552-1623, friend and patron of Galileo)

The first separate edition in English of the "foundation stone in the science of mechanics" (Grolier). "So great a contribution to physics was Two New Sciences that scholars have long maintained that the book anticipated Isaac Newton's laws of motion" (Hawking, 397). Galileo's work was first translated into English by Thomas Salusbury and appeared in However, nearly all copies of that volume, published in 1665, were consumed in the Great Fire of London in 1666, with only about ten copies of Vol. II, Part I being known to have survived. Galileo’s Discorsi is a mathematical dialogue on kinematics and a variety of physical problems (including: matter, sound, and light); it also contains philosophical components dealing with the nature of mathematics and the role of experiment and reason in science. The Discorsi replaced the Aristotelean notion of motion with a new one based in inertia and principles derived from falling bodies, projectiles, and the pendulum. “It was upon his [Galileo’s] foundation that Huygens, Newton and others were able to erect the frame of the science of dynamics, and to extend its range (with the concept of universal gravitation) to the heavenly bodies” - PMM 130. 

Widely considered the first modern textbook of physics, the "two new sciences" were "the engineering science of strength of materials and the mathematical science of kinematics. The first, as Galileo presents it, is founded on the law of the lever; breaking strength is treated as a branch of statics. The second has its basis in the assumption of uniformity and simplicity in nature, complemented by certain dynamic assumptions" (DSB V, p.245).

Galileo’s last published work presents its groundbreaking scientific discoveries in the form of a complex dialogue involving three interlocutors, Salviati, Sagredo and Simplicio (who had also appeared in his troublesome Dialogue concerning the two chief world systems of 1632) and an unnamed Academician, ostensibly Galileo himself. This dialogue takes place over four days, each day addressing an area of physics and a host of ancillary topics. The fourth day discusses the motion of projectiles, forming a basis for early military engineering; Galileo made use of Tartaglia's work on trajectories and in this work he demonstrated their parabolic trajectories.

Quarto (250 x 195mm). Title printed in red and black, numerous diagrams in text, one engraved table, advertisement leaf (light soiling to title and a few other leaves, table loose, overall very fresh). Contemporary paneled calf, ruled in blind (neatly rebacked with original spine preserved, light repair to corners). Preserved in custom clamshell. Book #Bv2423.