This is a discussion of the notion of acceleration of time in different natural processes, as occurring in Francis Bacon’s Sylva Sylvarum, Century IV, experiments [301-354].
Keywords: acceleration of time: of liquors, of putrefaction, of growth, of stature, vivification, spirits.
Among the inter magnalia naturae which Bacon discusses in his works, the acceleration of time is one of the most important, for Bacon places it next to the creation of matter in divine miracles (introduction to century IV). The Verulam presents a twofold motivation for pursuing the acceleration of time in nature: “it is a spur to nature” and “of good use”. From the first observation one can infer that Bacon seems to do nothing than to present a process which takes place inside the boundaries of nature and which normally would develop in a larger period of time. Here is a presentation of some of Bacon’s most important examples of acceleration of time: acceleration of liquor’s clarification, of maturation, of putrefaction, of birth and of growth and stature.
1. Acceleration of liquors’ clarification.
Bacon talks about different types of accelerations and starts with discussing at some length the acceleration of liquors’ clarification. Here is, in a word, the strategy for achieving this task: “to know the means of accelerating clarification, we must first know the causes of clarification” . And among the causes listed, the first one can be called mechanical (weight, motion, activity, percolation, etc): the separation between grosser and finer parts of the liquor; the second cause is the settlement of equal equilibrium between tangible and pneumatic and the third cause is the refining of the spirit itself.
After Bacon lists the causes, he moves to proposing some trails, which can be classified under three categories of experiments, as follows:
▪ instances of separation: , , , – percolation 
▪ instances of equilibrium: , 
▪ instances of the refining of the spirit , , 
2. Acceleration of maturation .
Bacon talks of several types of accelerations of maturation: of drinks, fruits, impostures and ulcers, metals; he also mentions that the one on “impostures and ulcers” will be tackled throughout the section “experiments medicinal”, but this has never appeared among Sylva’s entries.
a) maturation of drinks takes place by the congregation of spirits together and so it looks similar with clarification of liquors: “is effected partly by the same means that clarification is…” . Examples of maturation of drinks are seen in must, wine and vinegar . It is worth to note here that Bacon is plain here that spirits are endowed with motions, as the following examples suggest: “enforcing the motion of the spirit” … “enforce the spirits by some mixtures” . As in general for Bacon, the spirit seems to be here a more fundamental concept as motion. The question that opens up is what is the relationship between spirit and motion and the readers of this post are invited to express their opinion on this issue, too.
b) maturation of fruits is done by “calling forth of the spirits of the body outward…”, by digestion of the grosser parts – by heat, motion, attraction, putrefaction. Putrefaction therefore starts with maturation .
During his talk of maturation, Bacon also makes an interesting remark on the possibility to perform transmutations on bodies: “But we, when we shall come to handle the version and transmutation of bodies, and the experiments concerning metals and minerals, will lay open the true ways and passages of nature, which may lead to this great effect” . One important question to ask here is: are those transmutations done within the boundaries of nature or not? Later on in the same entry, Bacon seems to be saying yes to the first option and contrasts it with the alchemist interpretation: “The sixth is, that you give time enough for the work; not to prolong hopes (as the alchemists do), but indeed to give nature a convenient space to work in”.
3. (Inducing and) Acceleration of putrefaction.
Putrefaction precedes generation, both being taken as the true boundaries of nature “or the guides to life and death” (introduction before ). Putrefaction is defined as being caused by a motion “confused and inordinate”, while on the contrary, vivification appears when the motion “has a certain order” .
4. Experiment solitary touching the acceleration of birth.
Bacon gives here two causes for the acceleration of birth: the rapid development of the embryo and the expulsion of it from the mother . He altogether rejects the old thesis that this acceleration might suffer decisively from astral influences.
5. Experiment solitary touching the accelerating of growth and stature (of children) 
Bacon lists here three causes for speeding up growth and stature.
- Plenty of nourishment
- Nature of nourishment
- Exciting natural heat
The first one is not always recommended for it can be hurtful for the child. The second warns us not to feed the children with over-dry nourishment for this impedes growth. And finally, cold nourishment should be avoided in childhood for generally “heat [and not cold] is requisite for growth”, though a mature man should be more open to cold for it helps with condensing and preserving the spirit.