LECTURE LX. 



ON THE HrSTORY OF TERllESTRIAL PHYSICS. 



jLhROUGHOUT the whole of nature, we discover a tendency to the mul- 

 tiplication of life, of activity, and of enjoyment: man is placed at the head 

 of terrestrial beings, the only one that comprehends, and that can trace, in a faint 

 outline, the whole plan of the universe. We have seen the innumerable lumina- 

 ries which enliven the widely expanded regions of immeasurable space, with their 

 brilliant, but distant emanations of light and heat. Revolving round them at 

 lesser intervals, and cherished by their fostering influences, are their planets 

 and their comets; those preserving their distances nearly equal, and these, 

 ranging more widely from the upper to the lower regions, without limits to 

 their numbers or to their motions. Having conjectured what might possibly 

 exist on other planetary globes, we descended to our own, and examined its 

 structure and the proportions of its parts. Next we studied the general pro- 

 perties of the matter within our reach, and then the particular substances 

 or qualities that are either not material, or are distinguished by very 

 remarkable properties from other matter, as we found them concerned in 

 the phenomena of heat, of electricity, and of magnetism; and we after- 

 wards examined the combinations of all these, in the great atmospherical 

 apparatus of nature, which serves for the exhibition of meteorological phe - 

 nomena. The forms and the laws of animal and vegetable life have been tlie 

 last objects of our inquiries; but the magnitude of some departments of 

 natural history, and the obscurity of others, have prevented our entering 

 more than .superficially upon any of them. 



Of the gradual advancement of astronomy we have already taken a his- 

 torical view. With respect to the other sciences comprehended under 

 the denomination of proper physics, the progress of discovery has generally 

 been slow, and frequently casual. The ancients had little or no substantial 



