their condition allows, to use the same, as rules of practice; and thus, in some cases, to equal, regulate, subdue, or even excel nature by art. So that upon the discovery of forms depends the perfection of philosophy, or the enlargement of the human knowledge and power.

This business of discovering forms being of such infinite importance, the author endeavours to make it as intelligible as its nature will admit, in the present imperfect state of minds and things; and shews, that in effect, to discover forms, is the same thing as having some extremely intelligent person, ready at hand, to consult upon all occasions concerning the works of nature, the search after forms being like asking of questions; and the discovery of them like the receiving of answers: so that there is no point of theoretical knowledge, no rules, or directions, required in practice, but what may as well be had by the discovery of forms, as if nature herself were to speak, and tell men how she works; and what they must do to imitate, lead, or command her. For to find a form, is to find a nature, that shall be equivalent to the nature sought; so as when present, or absent, to constitute, or abolish, that nature respectively. Or, to make the conception still plainer, the form of a thing is the effective power, or physi cal act, by which it exists. Thus if the nature

sought were fluidity, or the means of converting charcoal into a fluid mass; and it be found, by a proper course of enquiry, called the Investigation of Forms, that the form, law, or nature of fluidity consists in a certain size, or smallness of parts, joined with a certain motion; this is finding a nature equivalent to, or convertible with, fluidity: whence men are directed to give this smallness of parts to charcoal, along with the particular motion disccvered; upon which, the charcoal will put on the nature of fluidity: and accordingly, if charcoal be reduced to pow der, and detained in a close vessel in the fire, till its parts are sufficiently agitated, it will have the appearance of a fluid. And this may illustrate, or give some sensible image of the thing under consideration; and shew that both a perfect theory, and a perfect practice, depend upon the discovery of forms.

But as a pernicious custom of leaving experience, and running into abstract speculations, has prevailed; the author judges it much the surest method to begin to raise the sciences from practice; or to let the practical part describe and limit the theoretical, or contempla, tive. He therefore enquires what are the best practical rules that could be wished for; and finds them afforded by the discovery of forms: so that, on all accounts, the investigation of

orms is the first and principal thing that can be gone upon, in order to improve philosophy, and perfect the sciences; especially as, at the same time, these forms also afford, according to what was before observed, perfect theoretical axioms, as well as the best practical rules, canons, or precepts.

On this footing, the requisites to practice must be first considered; that is, the means of enlarging the human power, and enabling it to introduce all possible changes upon matter; or produce all possible effects. And here the author shews there are two different kinds of canons, or axioms, for producing transmutations, or changes; viz. one with regard to bodies, as they are an assemblage, or combination, of a set of properties; as gold is of a determinate gravity, ductility, &c. and another that depends upon finding the way wherein nature herself proceeds in the generation or production of bodies; as how gold was made in the bowels of the earth, &c. the first kind of axiom shews how things are made by introducing a certain set of simple properties into a mass of matter susceptible thereof; and the second directs the way of proceeding by seminal properties, as it were; or beginning with the rudiments of things, and using the same first matter, and means, that nature herself employs. And where the power

of mankind cannot possibly reach to operate, as in the heavens, &c. yet even there the facts of nature may be sought; and her laws and manner of proceeding discovered. The whole process of finding these axioms, and discovering the causes of things, the author calls by the name of the interpretation of nature.

This interpretation of nature has two parts; the first with regard to the forming of axioms from experience; and the second with regard to the contriving of new experiments from axioms. The first requires proper helps for the mind; or assistances for the sense, the memory, and the reason and hence, before this interpretation of nature can be exercised to advantage, a just and extensive history of nature and art must be proeured; as the first matter out of which axioms are to be framed, forms discovered, and philosophy built.

This history is not to be a rhapsody, or confused collection of all sorts of Matters, thrown together on a heap; but to be carefully digested, and formed into regular tables, or packets of instances, and prepared parcels of history; as the pillars, the rafters, &c. are made ready for a building. And when such a history shall be procured, the understanding is not to work upon it by means of its own simple natural powers; but is to be assisted by the use of ge

ge

nuine induction; and thus enabled to practise the art of investigating forms.

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1. The subject of enquiry being chose; suppose, for example, the form of heat; all the instances wherein heat is found are to be duly collected, and ranged in a particular table; so as to afford a clear view of these instances to the mind. A distinct enumeration must, therefore, be made of all the things that are hot; as the sun's rays, flame, ignited iron, &c. 2. A collection is to be made, and a regular table formed, of those things wherein heat does not reside: but as this might swell the table immoderately; only such things need be mentioned as approach near to the nature of the former, except in the single property of heat, which they are without; such as the rays of the moon, certain corruscations, glow-worms, &c. that afford light, but no heat. And thus the things that are not hot, being placed over against the things that are hot, the mind may distinctly compare the two sorts together. 3. A table must next be formed, to shew the different degrees of heat, that are found in different things; or to exhibit, at one view, all the instances of heat, with regard to more and less : beginning with such things as are not sensibly hot to the touch, and proceeding gradually to the most violent heats, as those of volcanos, the burning concave, &c.