GALILEO AND HIS JUDGES. 59 



Our philosopher, wise as he was, had not freed 

 himself from the antiquated notion that some bodies 

 were essentially heavy and others light, which latter 

 had no tendency to descend ; not thereby meaning 

 comparatively light substances, but such as were 

 absolutely free from the action of gravity ; the fact not 

 being then understood that it is only the resistance of 

 the air that prevents the smallest feather from falling 

 to the ground as quickly as a cannon-shot. 



Another mistake into which he falls is that of 

 maintaining, in answer to the argument that the 

 diurnal rotation of the Earth would cause objects to 

 fly off from the surface at a tangent, that no amount 

 of velocity of rotation would be sufficient for such 

 a result to follow ; whereas, it is well known to 

 modern students of mechanics that if a certain very 

 high velocity of rotation were reached, the centrifugal 

 force would overcome that of gravity, and objects 

 would be projected from the surface of the Earth 

 in the direction of the tangent at that point. 



Some irrelevant arguments occur, of which, no 



che voi sappiate dell' essenza del movente le Stelle in giro ; 

 eccetuatone il riome, che a questa e stato posto, e fatto familiare, e 

 domestico per la frequente esperienza, che mille volte il giorno noi 

 ne veggiamo ; ma non e, che realmente noi intentiamo piu, che 

 principio, o che virtu sia quella, che muove la pietra in giu, di quel 

 noi sappiamo chi la muova in sii, separata del 'proiciente ; o chi 

 muova la Luna in giro, eccettoche (come ho detto) il nome, che 

 piu singolare e proprio gli abbiamo assegnato di gravita ; doveche 

 a quello con tennine piu generico assegniamo virtu impressa, a 

 quello diamo intelligenza o assistente, o informante \ e a infiniti altri 

 moti diamo loro per cagione la natura." 



