Thus he devoted some attention to the quadrature of surfaces and the cubature of solids, which he accomplished, in some of the simpler cases, by an original method which he called the "Method of Indivisibles"; but he lost much of the credit of the discovery as he kept his method for his own use,while Bonaventura Cavalieri published a similar method which he himself had invented.
The Arithmetica infinitorum relates chiefly to the quadrature of curves by the so-called method of indivisibles established by Bonaventura Cavalieri in 1629 (see Infinitesimal Calculus).
The simple nature of the alkalies Lavoisier considered so doubtful that he did not class them as elements, which he conceived as substances which could not be further decomposed by any known process of analysis - les molecules simples et indivisibles qui composent les corps.
Torricelli, by employing the "method of indivisibles," deduced that the area was exactly three times that of the generating circle; this result had been previously established in 1640 in France by G.
Cavalieri's " indivisibles " into the infinitesimal calculus, all accomplished during the 17th century, immeasurably widened the scope of exact astronomy.