BOOK It] INSTANCES OP THE CROSS. 503 



certain. In the mean ^.vhile, both in this respect and many 

 others, it will readily be seen how deiicient we are in natural 

 history, since we are forced to hav r e recourse to suppositions for 

 examples, instead of ascertained instances. 



Again, let the required nature be the discursive power of the 

 mind. The classification of human reason and animal instinct 

 appears to be perfectly correct. Yet there are some instances ot 

 the actions ot brutes which seem to show that they, too, can 

 syllogise. Thus it is related, that a crow, which had nearly 

 perished from thirst in a great drought, saw some water in the 

 hollow trunk o( a tree, but as it was too narrow for him to get 

 into it, he continued to throw in pebbles, which made the water 

 rise till he could drink; and it afterwards became a proverb. 



Again, let the required nature be vision. The classification 

 appears real and certain, which considers light as that which ia 

 originally visible, and confers the power of seeing ; and colour, 

 as being secondarily visible, and not capable oi being seen with 

 out light, so as to appear a mere image or modification of light. 

 Yet there are instances oi alliance in each respect ; as in snow 

 when in great quantities, and in the flame of sulphur ; the one 

 being a colour originally and in itself light, the other a light 

 Teririnir towards colour. 1 &quot; 



XXXVI. In the fourteenth rank of prerogative instances, we 

 will place the instances of the cross, borrowing oiir metaphor 

 from the crosses erected where two roads meet, to point out the 

 different directions. We are wont also to call them decisive and 

 judicial instances, and in some cases instances of the oracle and 

 of command. Their nature is as follows. When in investigating 

 any nature the understanding is. at it were, balanced, and un 

 certain to which of two or more natures the cause ot the required 

 nature should be assigned, on account of the frequent and usual 

 concurrence of several natures, the instances of the cross sho\v 

 that (lie union ot one nature with the required nature is firm 

 and indissoluble, whilst that of the other is unsteady and 

 separable ; by which means the question is decided, and the 

 first is received as the cause, whilst the other is dismissed and 

 rejected. Such instances, therefore, afford great light, and are 

 of great weight, so that the course of interpretation sometimes 

 terminates, and is completed in them. Sometimes, however, 

 ihey are found amongst the instances already observed, but 

 they are generally new, being expressly and purposely sought 

 for and applied, and brought to light only by attentive and 

 active diligence. 



For example : let the required nature be the flow and ebb of 

 the sea, which is repeated twice a day, at intervals of six hours 



* Snow reflects light, but is not a source of light. 



