PleascMit Ways in Science. 269 



Being parodoxically inclined, we will add that such a fixed 

 point may be a rapidly moving one, and will do just as well, 

 nay, in most cases, it would not enjoy the merit of what we 

 call "fixity " if it did not travel at a great rate. Suppose 

 Westminster Abbey were miraculously impressed with, and 

 enabled to perform, the duty of standing still, while Charing 

 Cross and the Houses of Parliament went with the earth's 

 surface on its diurnal tour ; the angle made by lines connecting 

 these buildings, as seen from Charing Cross, would rapidly 

 change, and the inhabitants of London, not let into the secret, 

 might think the old abbey was running away. As the earth 

 moves, carrying along with it its burden of hills, buildings, and 

 trees, the " fixity " of any one of these objects depends upon 

 its partaking of exactly its own share of the motion common 

 to all. The motion of the earth, from west to east, does not 

 hinder the railway from carrying us from east to west. It is 

 as easy to walk from St. Paul's to Chariug Cross, as from 

 Charing Cross to St. Paul's, and no passenger feels whether 

 he is going as the earth goes, or in opposition to her diurnal 

 course. 



In order to become aware of motion we want comparison. 

 An object moving on the earth's surface in a direction or with 

 a velocity different from the direction and velocity common to 

 all territorial objects, manifests its special motion by taking 

 up a new place in reference to other objects, and we assume 

 that the other objects have not moved because their position 

 is unchanged with reference to each other. 



In the smoothest form of travelling, if we do not look at 

 objects for comparison, we scarcely know that we are moved. 

 If a jerk occurs, one part of our body immediately complains 

 that its position, with reference to other parts, is violently 

 changed. An extreme instance of this sort of action is 

 when a cannon ball takes off a leg by communicating to it a 

 velocity with which the rest of the unfortunate individual can- 

 not possibly keep pace. 



The velocity with which certain motions take place is far 

 beyond our possibility of conception. We see them expressed 

 in Hues of figures that soon cease to have any meaning which 

 understandings can grasp. An uneducated man has no con- 

 ception of a few thousands. To a savage, all beyond twenty 

 or a hundred is vaguely presented as a great many. An ordi- 

 nary man of business grasps the notion of a million, though 

 only to some extent. Billions, trillions, and their connexions, 

 seem all alike — vast, vague, and not to be comprehended. An 

 astronomer or mathematician penetrates their mysteries up to 

 a certain point ; but he is soon brought to a condition of non- 

 apprehension, and gigantic numbers come at last to mean to 



