ESSENTIAL AND PECULIAR. 



47 



became manifest, that the planets and comets, reciprocally acting and 

 acted upon, must deviate a little from the laws of that perfect ellipse which * 

 they would precisely follow if they had only to obey the action of the sun : 

 it was manifest, that the satellites of the different planets exposed to the 

 complicated action of the sun, and of each other, must evince a similar 

 disturbance : that the corpuscles which composed the different heavenly 

 bodies in their formation, perpetually pressing toward one common centre, 

 must necessarily have produced, in every instance, a spherical mass : that 

 their rotatory motion must at the same time have rendered this spherical 

 figure in some degree imperfect, and have flattened these masses at their 

 poles ; and, finally, that the particles of immense beds of water, as the 

 ocean, easily separable as they are from each other, and unequally operated 

 upon by the sun and the moon, must evince such oscillations as the ebbing 

 and flowing of the tides. The origin, progress, and perfection of these 

 splendid conjectures, verifications, and established principles, were com- 

 municated in two distinct books, known to every one under the titles of 

 his " Principia" and his " Optics ;" — books which, though not actually 

 inspired, fall but little short of inspiration, and have more contributed to 

 exalt the intellect of man, and to display the perfections of the Deity, than 

 any thing upon which inspiration has not placed its direct and awful stamp. 



LECTURE V. 



ON THE PROPERTIES OF MATTER, ESSENTIAL AND PECULIAR. 



(The subject continued. ) 



We closed our last lecture with remarks on the universal operation of 

 the common principle of gravity over matter in all its visible forms, from 

 the minutest shapes developed by the microscope, to the mightiest suns and 

 constellations in the heavens. But we observed, also, that independently 

 of this universal and essential power of attraction, matter possesses a vari- 

 ety of pecuHar attractions dependent upon circumstances of limited influ- 

 ence, and which consequently render such attractions themselves of local 

 extent. 



These I will now proceed to notice to you in the following order 1st, 

 The attraction of homogeneous bodies towards each other, which is de- 

 nominated, in chemical technology, the attraction of aggregation ; 2dly, the 

 attraction of heterogeneous bodies towards each other, under particular 

 circumstances, which in its more obvious cases is denominated capillary 

 attraction : 3dly, The attraction of bodies exhibiting a peculiar degree of 

 affinity to each other, and which is denominated elective attraction : 4thly, 

 The attraction of the electric fluid ; and, 5thly, That of the magnetic. 



I. The law of physics which has rendered every material substance capa- 

 ble of attracting and being attracted by every other material substance 

 seems at the same time to have produced this power in a much stronger 

 degree between substances of like natures. Thus, drops of water 

 placed upon a plate of dry glass have a tendency to unite, not only when 

 they touch, but when in a state of vicinity to each other ; and globules of 

 quicksilver still more so : and it is this kind of attraction which is called 

 ^he attraction of aggregation. And in both these cases the attraction in 



Ik 



