OF NATURAL PHILOSOPHY. 183 



them with each other, before we can tell which are 

 the instances thus deservedly entitled to the highest 

 consideration. And, after all, after much labour in 

 vain, and groping in the dark, accident or casual 

 observation will present a case which strikes us at 

 once with a full insight into a subject, before we 

 can even have time to determine to what class its 

 prerogative belongs. For example, the laws of crys- 

 tallography were obscure, and its causes still more 

 so, till Haiiy fortunately dropped a beautiful crystal 

 of calcareous spar on a stone pavement, and broke 

 it. In piecing together the fragments, he observed 

 their facets not to correspond with those of the 

 crystal in its entire state, but to belong to another 

 form; and, following out the hint offered by a 

 "glaring instance" thus casually obtruded on his 

 notice, he discovered the beautiful laws of the 

 cleavage, and the primitive forms of minerals. 



(192.) It has always appeared to us, we must 

 confess, that the help which the classification of in- 

 stances, under their different titles of prerogative, 

 affords to inductions, however just such classification 

 may be in itself, is yet more apparent than real. 

 The force of the instance must be felt in the mind, 

 before it can be referred to its place in the system ; 

 and, before it can be either referred or appretiated, 

 it must be known ; and when it is appretiated, we 

 are ready enough to interweave it in our web of in- 

 duction, without greatly troubling ourselves with 

 enquiring whence it derives the weight we acknow- 

 ledge it to have in our decisions. However, since 

 much importance is usually attached to this part of 



