Borelli's major scientific achievements are focused on his investigation into
biomechanics. This work originated with his studies of animals. His publications,
De Motu Animalium I and
De Motu Animalium II, borrowing their title from
the Aristotelian treatise, relate animals to machines and utilize mathematics to prove his theories. The first volume covers biomechanical and muscular action in humans and animals (how muscles move while living beings walk, run, swim, jump, and fly). The second volume discusses the physiology of human organs, namely the lungs and heart. The anatomists of the 17th century were the first to suggest the contractile movement of muscles. Borelli, however, first suggested that 'muscles do not exercise vital movement otherwise than by contracting.' He was also the first to deny corpuscular influence on the movements of muscles. This was proven through his scientific experiments demonstrating that living muscles did not release corpuscles into the water when cut. Borelli also recognized that forward motion entailed the movement of a body's center of gravity forward, which was then followed by the swinging of its limbs in order to maintain balance. His studies also extended beyond muscle and locomotion. In particular, he likened the action of the heart to that of a piston. For this to work properly he derived the idea that the arteries have to be elastic. For these discoveries, Borelli is labeled as the father of modern
biomechanics, and the
American Society of Biomechanics uses the Borelli Award as its highest honor for research in the area. Along with his work on
biomechanics, Borelli also had interests in
physics, specifically the orbits of the
planets. Borelli believed that the
planets were revolving as a result of three forces. The first force involved the planets' desire to approach the sun. The second force dictated that the planets were propelled to the side by impulses from sunlight, which is
corporeal. Finally, the third force impelled the planets outward due to the sun's revolution. The result of these forces is similar to a stone's orbit when tied on a string. Borelli's measurements of the orbits of satellites of Jupiter are mentioned in Volume 3 of Newton's
Principia. , by Giovanni Alfonso Borelli, in
De Motu Animalium, 1680 Borelli is also considered to be the first person to consider a
self-contained underwater breathing apparatus along with his early submarine design. The exhaled gas was cooled by sea water after passing through copper tubing. The
helmet was brass with a glass window and 0.6 m (2 ft) in diameter. The apparatus was never likely to be used or tested. He discovered the principle of the
heliostat more than sixty years before
Willem 's Gravesande.
Other works Borelli also wrote: •
Delle cagioni delle febbri maligne della Sicilia negli anni 1647 e 1648 (Cosenza, 1649) •
Euclides Restitutus (Pisa, 1658) • •
Theoricae Mediceorum planetarum ex causis physicis deductae (Florence, 1666) • • • • ==References==