NO I U AT ORGANUM. 309 



This we arc accustomed to call the Table, of Existence and 

 Presence* 



xii. Secondly, a presentation to the Understanding must be made 

 of Instances which are wanting in the given Nature ; because the 

 Form (as we have said) ought no less to be absent where the given 

 Nature is absent, than present where it is present. Hut to follow this 

 out in all cases would be useless ; and so we must subjoin the nega 

 tives to the affirmatives, and only look into the absence of the Nature 

 in these subjects which are mcst allied to those others in which the 

 given Nature is inherent and apparent. This we are accustomed to 

 call the Table of Declination, or of Absence in Proximity. 



Instances in Proximity wanting the \atitre of Heat. 



First Instance, Negative or Subjunctive, to the First Affirmative 

 Instance. 



1. The rays of the moon, of the stars and comets, arc not found to 

 be hot to the touch ; nay, rather, the sharpest cold is usually observed 

 at time of full moon. Hut the larger fixed stars, when the sun passes 

 under or approaches them, are thought to increase and tensify its 

 heat, as is the case when the sun stands in the sign of the Lion, and 

 in the clog days. 



To the Second. 



2. The rays of the sun in the mid region of the air, as they call it, 

 give no heat ; and the reason which is commonly given (or this is not 

 a bad one, viz., that that region is neither near enough the body of 

 the sun, whence the rays emanate, nor to the earth, whence they arc 

 reflected, to be much affected by them. And this is dear from the 

 fact, that on the tops of mountains (which arc not very high) the snow 

 is perpetual. Hut, on the other hand, it has been remarked by some 

 that on the summit of the 1 cak of TcnerilTe, and also on the Peruvian 

 Andes, the very tops of the mountains arc devoid of snow, which lies 

 only in spots lower clown the ascent. And, moreover, the air on these 

 same summits is found to be far from cold, but only rare and keen ; 

 so much so, that on the Andes it irritates and wounds the eyes by its 

 excessive sharpness, and even irritates the orifice of the stomach, and 

 induces vomiting. And it has been remarked by the ancients, that so 

 great is the rarity of the air on the top of Olympus, that it was neces 

 sary for those who ascended to take with them sponges moistened 

 with vinegar and water, and to apply them continually to the mouth 

 and nostrils, the air being so rare as not to suffice for respiration. 

 And so serene is that summit said to have been, and so free from rain, 

 and snow, and wind, that when sacrifices were offered there, the 

 letters traced in the ashes of the sacrifices on the altar of Jupiter 

 remained undisturbed until the next year. And even at the present 

 day the ascent of the Peak of Teneriflc is made by night, and not by 

 day ; and shortly after sunrise travellers are warned and urged by 

 their guides to descend as quickly as possible, on account of the 



