FRANCIS BACON 13 



ternal heat of animals; dry heats, such as the heat of ashes, lime, 

 warm sand ; in short, the nature of every kind of heat, and its degrees. 



We should, however, particularly attend to the investigation and 

 discovery of the effects and operations of heat, when made to approach 

 and retire by degrees, regularly, periodically, and by proper intervals 

 of space and time. For this systematical inequality is in truth the 

 daughter of heaven and mother of generation, nor can any great 

 result be expected from a vehement, precipitate, or desultory heat. 

 For this is not only most evident in vegetables, but in the wombs of 

 animals also there arises a great inequality of heat, from the motion, 

 sleep, food, and passions of the female. The same inequality pre- 

 vails in those subterraneous beds where metals and fossils are perpetu- 

 ally forming, which renders yet more remarkable the ignorance of 

 some of the reformed alchemists, who imagined they could attain 

 their object by the equable heat of lamps, or the Hke, burning 

 uniformly. Let this suffice concerning the operation and effects 

 of heat; nor is it time for us to investigate them thoroughly before 

 the forms and conformations of bodies have been further examined 

 and brought to light. When we have determined upon our models, 

 we may seek, apply, and arrange our instruments. 



IV. The fourth mode of action is by continuance, the very steward 

 and almoner, as it were, of nature. We apply the term continuance 

 to the abandonment of a body to itself for an observable time, guarded 

 and protected in the mean while from all external force. For the 

 internal motion then commences to betray and exert itself when the 

 external and adventitious is removed. The effects of time, however, 

 are far more delicate than those of fire. Wine, for instance, cannot 

 be clarified by fire as it is by continuance. Nor are the ashes produced 

 by combustion so fine as the particles dissolved or wasted by the 

 lapse of ages. The incorporations and mixtures, which are hurried 

 by fire, are very inferior to those obtained by continuance; and the 

 various conformations assumed by bodies left to themselves, such 

 as mouldiness, etc., are put a stop to by fire or a strong heat. It is 

 not, in the mean time, unimportant to remark that there is a certain 

 degree of violence in the motion of bodies entirely confined ; for the 

 confinement impedes the proper motion of the body. Continuance 

 in an open vessel, therefore, is useful for separations, and in one 

 hermetically sealed for mixtures, that in a vessel partly closed, but 



