DIFFUSION OF ACTION BY MATTER. 7 



pebbles on the mirror-like surface of a calm lake. 

 The action is diffused in every direction from the 

 central point, in wave rings, that continue enlarg- 

 ing successively, until the original impulse "im- 

 parted by the hand to the pebble spreads to all 

 the surrounding shores. These illustrations serve 

 to show that there is no limitation to the diffusion 

 of an impulse ; as is tested on a sublime scale by the 

 infinite extent of the transmission of gravitating 

 force and light throughout infinite space. These 

 facts, and all other knowledge of the external 

 world, being obtained by the instrumentality of 

 the nerves of sensation, there is consequently 



SLOW PROGRESS OF SCIENCE BY EXPERIMENTAL 

 INVESTIGATION. 



In Europe, the earliest attempts to learn the 

 properties of matter were made with crucibles 

 and alembics, excited by heat to develop re- 

 actions. So fearful were superstitious people of 

 the existence of mysterious powers and evil spir- 

 its in peculiar kinds of substances, that exper- 

 imenters were obliged to work in secret places 

 to find out the real properties of matter. So 

 occult appeared the causes of the behavior of 

 molecules toward each other in uniting inter- 

 changeably, and separating, that this new science 

 was denoted " Alchemy," from the Arabic KIMIA, 

 a mystery. 1 



1 Through Arabia and Egypt most of the original mathematical and 

 chemical sciences of the people of Asia were introduced into Greece 



