NOVUM ORGANUM 145 



the tube, divided into as many degrees as you 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 exhibited 

 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 sunshine, the heat 

 of the breath, and much more, that of the hand placed on 

 the top of the tube, immediately causes an evident depres 

 sion of the water. We think, however, that the spirit of 

 animals possesses a much more delicate susceptibility 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 sen 

 sible of heat, which have been recently changed and con 

 tracted by cold, as snow and ice; for they begin to be dis 

 solved 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 toward 

 their centre. 29 When heated, however, they retain their 

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

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



29 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 differ 

 ent 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 gen 

 erally cold to the touch. The convenience of fixing wooden handles to vessels 

 containing hot water illustrates these observations. 



