Archimedes

"The centre of gravity of a parallelogram is the point of intersection of its diagonals."

"In any triangle the centre of gravity lies on the straight line joining any angle to the middle point of the opposite side."

"The centre of gravity of any cylinder is the point of bisection of the axis."

"If two equal weights have not the same centre of gravity, the centre of gravity of both taken together is at the middle point of the line joining their centres of gravity."

"How many theorems in geometry which have seemed at first impracticable are in time successfully worked out!"

"Equal weights at equal distances are in equilibrium and equal weights at unequal distances are not in equilibrium but incline towards the weight which is at the greater distance."

"The centre of gravity of any parallelogram lies on the straight line joining the middle points of opposite sides."

"Two magnitudes whether commensurable or incommensurable, balance at distances reciprocally proportional to the magnitudes."

"Those who claim to discover everything but produce no proofs of the same may be confuted as having actually pretended to discover the impossible."

"Noli turbare circulos meos. or Noli tangere circulos meos."

"δῶς μοι πᾶ στῶ καὶ τὰν γᾶν κινάσω. [Dôs moi pâ stô, kaì tàn gân kinásō.]"

"The centre of gravity of any cone is [the point which divides its axis so that] the portion [adjacent to the vertex is] triple [of the portion adjacent to the base]."