OF NATURAL PHILOSOPHY. 39 



for him in the endeavour to discover, as far as our 

 faculties will permit, what are these primary qualities 

 originally and unalterably impressed on matter, and 

 to discover the spirit of the laws of nature, which 

 includes groups and classes of relations and facts 

 from the letter which, as before observed, is pre- 

 sented to us by single phenomena : or if, after all, 

 this should prove impossible ; if such a step be 

 beyond our faculties ; and the essential qualities of 

 material agents be really occult, or incapable of 

 being expressed in any form intelligible to our un- 

 derstandings, at least to approach as near to their 

 comprehension as the nature of the case will allow ; 

 and devise such forms of words as shall include and 

 represent the greatest possible multitude and variety 

 of phenomena. 



(30.) Now, in this research there would seem one 

 great question to be disposed of before our enquiries 

 can even be commenced with any thing like a pros- 

 pect of success, which is, whether the laws of nature 

 themselves have that degree of permanence and 

 fixity which can render them subjects of systematic 

 discussion ; or whether, on the other hand, the qua- 

 lities of natural agents are subject to mutation from 

 the lapse of time. To the ancients, who lived in 

 the infancy of the world, or rather, in the infancy 

 of man's experience, this was a very rational subject 

 of question, and hence their distinctions between 

 corruptible and incorruptible matter. Thus, accord- 

 ing to some among them, the matter only of the 

 celestial spaces is pure, immutable, and incorrupt- 

 ible, while all sublunary things are in a constant state 

 of lapse and change ; the world becoming paralysed 

 D 4, 



