116 NOVUM ORGANUM. 



please. You will then perceive, as the weather grows warmer 

 or colder, that the air contracts itself into a narrower space 

 in cold weather and dilates in the warm, which will be ex 

 hibited by the rising of the water as the air contracts itself, 

 and its depression as the air dilates. The sensibility of the 

 air with regard to heat or cold is so delicate and exquisite, 

 that it far exceeds the human touch, so that a ray of sun 

 shine, the heat of the breath, and much more, that of the 

 hand placed on the top of the tube, immediately causes an 

 evident depression of the water. We think, however, that 

 the spirit of animals possesses a much more delicate sus 

 ceptibility of heat and cold, only that it is impeded and 

 blunted by the grossness of their bodies. 



39. After air we consider those bodies to be most sensible 

 of heat, which have been recently changed and contracted 

 by cold, as snow and ice : for they begin to be dissolved and 

 melt with the first mild weather. Next, perhaps, follows 

 quicksilver ; then greasy substances, as oil, butter, and the 

 like ; then wood ; then water ; lastly, stones and metals, 

 which do not easily grow hot, particularly towards their 

 centre.* When heated, however, they retain their tempe 

 rature for a very long time ; so that a brick or stone, or hot 

 iron, plunged in a basin of cold water, and kept there for 

 a quarter of an hour or thereabouts, retains such a heat as 

 not to admit of being touched. 



40. The less massive the body is, the more readily it 

 grows warm at the approach of a heated body, which shows 

 that heat with us is somewhat averse to a tangible mass.f 



41. Heat with regard to the human senses and touch is 

 various and relative, so that lukewarm water appears hot if 

 the hand be cold, and cold if the hand be hot. 



Aph. 14. 



Any one may readily see how poor we are in history, 

 since in the above tables, besides occasionally inserting 

 traditions and report instead of approved history and au- 



* Bacon appears to have confounded combustibility and fusibility with sus 

 ceptibility of heat ; for though the metals will certainly neither dissolve as soon 

 as ice or butter, nor be consumed as soon as wood, that only shows that different 

 degrees of heat are required to produce similar effects on different bodies ; but 

 metals much more readily acquire and transmit the same degree of heat than any 

 of the above substances. The rapid transmission renders them generally cold to 

 the touch. The convenience of fixing wooden handles to vessels containing hot 

 water illustrates these observations. 



t Another singular error, the truth being that solid bodies are the best con 

 ductors ; but of course where heat is diffused over a large mass, it is less in each 

 part, than if that part also alone received the whole quantum of heat. 



