CHILDHOOD OF SCIENCE. 203 



than the balance of opposing forces, the surplus of the attraction 

 of the earth over the centrifugal force from its rotation. But, 

 said he, if you see an objection in the centrifugal force on the 

 surface of the earth, what is going to become of your own sys- 

 tem when that force is carried out to the distance of the sun and 

 moon and stars? What conceivable power can hold them in 

 a daily revolution about the earth? The school-men again 

 declared that the amazing rapidity of the flight 'of the earth 

 through space, a thousand miles in a single breath, would soon 

 leave its fragments strewed in its wake like the wreck of a storm- 

 driven ship. Galileo objected to this the inertia of matter, the 

 first great law of motion. If a body is once set in motion it will 

 continue in that motion until stopped by some other force. Thus 

 we as safely ride the flying world as the flying chariot. Again 

 they said, and it was the argument most strenuously insisted 

 upon, that if the earth w r as in motion from west to east then a 

 ball dropped from a high tower should fall, not at its base, but 

 to the westward of it, which was not the case. It was taught in 

 their books that an object let fall from the mast-head of a vessel 

 in motion would strike the deck at a certain distance behind the 

 foot of the mast. Much more then should the ball from the 

 tower fall away from the base. To this Galileo replied that 

 their quoted experiment would give no such result as was 

 .claimed. The object while falling from the mast-head would 

 continue to have the same forward motion that the ship had, and 

 would drop exactly at the foot of the mast ; and to convince 

 them that this was so, the experiment was actually tried on a 

 vessel in the harbor of Marseilles. 



Thus did this sturdy philosopher, while establishing the funda- 

 mental principles of mechanics, at the same time uproot the 

 errors of scholasticism and overthrow the dogmas of creed phil- 

 osophy. But in all this time he was gradually arousing against 

 himself the implacable enmity of that power which for a thous- 

 and years had been dealing out law to kings and creeds to states, 

 and had furnished as well opinions for the high as indulgences 

 for the low. Already he had been ordered to desist from his 

 bold teachings. But for the unresting mind of Galileo to cease 



